Bonaventure was born in 1217 at Bagnoregio in Latium. He was one of the most influential medieval theologians and philosophers. He spent much of his life connected with the University of Paris. He studied theology in the French capital. He lectured in university on the bible and he wrote a commentary on the sentences of peter the Lombard, and he received the degree of Doctor of theology, he joined the Franciscans order. Augustine and Francis were intemperately influenced by Bonaventure’s theology and it was deeply spiritual, he became the seventh minister of the order after Francis of Assisi in 1257. Bonaventure wrote a book called Disputed Questions on the mystery of the trinity while he was in Paris, This book has much on the issues involved with the trinity. Later he wrote a book known as The Journey of the Mind to God or Itinerarium. In this book he presents six steps for knowing god and coming into union with him. It begins with the cogitation of the beauty and order of what god has made, in his final steps he focused on contemplation of the goodness of pure being, for Bonaventure, the highest leel the human mind can reach is to become absorbed in the communication between the three person of the one god. His spiritual goal, in the final steps, he thus crafts around the triune reality of the father, son, and Holy Spirit.In that book third and fourth steps focus on the human soul. Bonaventure pursue the guide of Augustine which he wrote on his book on the trinity he suggest to know god, we as a human have to examine the image of god in ourselvesthat is the only way. As Augustine Bonaventure also had the idea of human image as a triune image. Bonaventure argued that the human soul has three components like memory, intellect, and will, within the one soul. Same as like this three aspects also correspond to the father, son, and Holy Spirit in the one god. Bonaventure took this from Augustine, Augustine did not overtly state but Bonaventure adds the factor. He says the intellect and will arise from memory, same as like the son and the Holy Spirit arise from the father. As ones intellect and will arise from the memory as wisdom is gained through remembered events, so the son, who is logos or word, proceeds from the father as his wisdom. Next Bonaventure makes a similar, though even more complex, parallel between the will arising from the both the memory and intellect and the spirit proceeding from the father and the son. Again as with Augustine, Bonaventure saw the procession of the son and spirit as integral to the doctrine of the trinity.ContentsThomas Aquinas was born around 1225 in Roccasecca, Italy.He the father of the Thomistic school of theology. Thomas was a most influential medieval thinkers of Scholasticism, he is a philosopher and Theologian. Thomas Aquinas was much influenced by Augustine’s discussions of the Trinitarian elements found in human beings, existence, life, and reason; and memory, intellect, and will. Thomas is also influenced by Aristotle and the Neo-Platonism of Pseudo-Dionysius. His most systematic discussion on the issue of the imago dei occurs in the first part of the Summa theologiae, it is entitled “The End or Term of the Production of Man.” Every article of the question refers to the imago dei. Aquinas focus on the intellectual soul as the locus of the image of God is so strong that he says the angels are more in the image of God than we are. “Thus the image of God is more perfect in the angels than in man, because their intellectual nature is more perfect. Aquinas states in his discussion of the Trinity that the doctrine is not known by natural reason but only by faith. “It is impossible to attain to the knowledge of the Trinity by natural reason. He admits that our knowledge of God’s essence is extremely limited and he says that we only know the essence of the soul by knowing its powers, that we know the powers by knowing the habits of first principles, and that we know these habits by knowing the acts. It means we only know about the Trinity because Jesus reveals this to us. And he decided that god only is all knowing. Aquinas says that we can discuss about god about what we know about him, but there still remains a much that we cannot know about him. His true being still remains a mystery to us.The trinity doctrine in the reformation era developed and understand by sola scripture, means bible and bible alone. But the Roman Catholics rejected the sole authority of scripture, they maintained the traditional dogma of the trinity as developed by Athanasius, Augustine, Aquinas and others. And most of them were compromised and adopted the philosophical foundation of the medieval period and few considered that this foundational was drawn from Greek philosophy largely and they were predetermined in their thinking and interpreted scripture. Here sola scripture did not means that they totally rejected all other sources of authority rather it stood for the subordination of all human authorities like emperors, councils, popes and traditions and scripture was the supreme authority.Martin Luther was born in 1483 in Eisleben. He taught theology at the new university of Wittenberg in 1508. He was interested in practical theology. Luther finds evidence for the Trinity in Gen. 1. First, there is the grammar of Gen. 1: l, in the beginning EIohim (plural) Bara (singular) the heavens and the earth, where the three persons together create as one. Elohim is consistently construed as a Trinitarian referent “let us make.” Luther identifies wherever in the Old Testament one finds God speaking about God, as if there were two persons, one may assume that the three persons of the Godhead are in view; and another is whenever the Hebrew Scriptures speak of the two persons of the Father and Son, the Holy Spirit is also necessarily present, for the Spirit speaks those words through the prophets. Luther affirmed the Augustinian insight that the external works (or works to the outside) of the Trinity are indivisible, while the internal works or activities admit and even necessitate distinctions. The Holy Trinity is one God, wherein the inseparable divine essence or substance refers to the total Trinity and majesty of God, which is shared commonly by all three persons. Luther spends more time rebutting subordinations, and he often seems to prefer Gospel arguments to specific exegetical consideration. Luther anticipates to some extent the twenty and twenty first century tendencies to begin with the historical man, Jesus of Nazareth, as depicted in the Gospels The Son is revealed in humanity, for the Son alone became man, He alone was conceived by the Holy Spirit, was born of the Virgin Mary, suffered and died for us, as our Creed informs us. However, it is also correct to say that God died for us, for the Son is God, and there is no other God but only more persons in the same Godhead. Luther’s three most striking candidates are Speaker, Spoken Word, and listener, the Father as the one who wants to comfort, the Son who prays for the comforter, and the Spirit who is the comfort.John Calvin was born on 1509, at Noyon, in Picardy. He published his first edition of institutes of the Christian religion, when he was at his 26 in Basel and he continued to revise and enlarge throughout his life. He was an extraordinary in his learning and he knew the ancient fathers as no one else in his century, he made commentaries which almost cover most of the books in bible. He was also known as the theologian who made the greatest contribution to the laying the solid foundation of the doctrine of the Trinity. His doctrine of the Trinity made the way for the most biblical understanding of God. Calvin’s doctrine of the Trinity did not come from a theological emptiness, rather from the theological controversies in the historical contexts in which they lived. Peter Caroli accused Calvin of Arianism. The accusation of Arianism against Calvin is ascribed to the inadequacies of the first edition of the “Institutes of the Christian Religion.” In May, 1537, Caroli brought the charge of Arianism against Farel and Calvin at a synod in Lausanne because they avoided the metaphysical terms Trinity and Person in the Confession.When Caroli asked Calvin to sign the Athanasian Creed with its damnatory clauses, Calvin refused to sign it because he thought that doing so is unjust and uncharitable. Calvin could not help showing a response to the accusation. Nonetheless, he did not have any intention to change his doctrine of the Trinity. Besides, he followed the footsteps of Luther when it came to defending traditional Trinitarian terminology. In his 1536 edition, Calvin briefly explained the traditional doctrine of the Trinity. He supported the unity of God by mentioning “one baptism” and “one faith “in Ephesians 4:5. At the same time he stressed that baptism should be administered in the name of the three Persons of the Trinity and the three Persons were the object of the faith. Calvin emphasised the importance of the divinity of Christ for the faith, and of the divinity of the Holy Spirit for communication with God the Creator and God the Redeemer. For Calvin, the question “What is God (quails it Deus)?”Is a very important question. This is because the knowledge of God was seriously distorted in the medieval age. This distortion of the knowledge of God naturally led to the distortion of worship. This made Calvin deeply examine the Bible. The God that he found in the Bible is the triune God.In the first twelve chapters of the book 1559 final edition of Institutes of the Christian Religion, he contrasts the biblical God with false gods. He begins to deal with the doctrine of the Trinity in chapter 13. And he deals with creation and providence from chapter 14 to chapter 18 based on the doctrine of the Trinity, he develops Christian epistemology and the doctrine of God in the first twelve chapters. And then he presents the doctrine of the Trinity. After presenting the doctrine of the Trinity, he deals with the most important two works that God does, creation and providence. According to Calvin, no one can obtain a pure knowledge of self without contemplating the face of God. And the contemplation of God leads believers to the experience of the Trinitarian God. Calvin says that God reveals Himself as the Triune God. That is, when we meet the sole God, we immediately meet the three, and vice versa.He begins to mention the person of the Holy Spirit along with the person of the Son. Then Calvin points out an important factor. Though each person of the Father, the Son, and the Holy Spirit is distinguishable, the Son and the Spirit is one God with the Father. This distinction does not indicate essence but interrelation among the three Persons. Rather he says that when we confess to believe in one God, a single, simple essence is understood under the name of God. At the same time we comprehend three persons in the essence. Calvin says that Christ has been called the Son of God not only because he was the eternal begotten Word but also because he took upon himself the person and office of the Mediator. He says that divine nature is common to all three persons. We should not separate the persons from the essence. But we should distinguish among the persons while the three persons remain within the essence, and that the three persons of the Godhead are consubstantial.The New Testament books are known as the earliest Christian writings which is available to us now. In that it was clearly present a father, a son, and a holy spirit. According to Matthew 28:19 “Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the son and of the Holy Spirit” (NKJV), each of the three beings was indisputably central to early Christian worship and belief.Basically the Christian doctrine of god arise from the thought of early Judaism. The Christianity came out and grew from the first century Jewish world and it was strongly monotheistic. The Jews strongly belief in one and only god and they stood apart from all religious group.The Shema is a prayer from Deuteronomy 6:4 “Hear, O Israel the Lord our god, the Lord is one,” In the first century A.D., it become one of the most universally practised prayer in Judaism and the Shema represents the monotheistic understanding central to the Jewish faith.Judaism encompassed a variety of thought groups, including Pharisees, Sadducees, Essenes, and other groups. On the whole the many different branches held this belief in common. Christianity which also hold the Hebrew Scriptures as authoritative, which shared the strong belief in monotheism.The Greco-Roman religious world abounded with many gods. As the Roman Empire expanded, ever more peoples and more gods joined the religious mix. The average city in the Roman Empire represented not only a widely diverse ethnic and national population, but also a broad array of pagan deities and temples.So in the minds of some philosophers they emerged a strong reaction against such as extreme excess of gods. The Greco-Roman philosophers they grew a strong surge of monotheism that recognized one ultimate god who transcended not only the visible world. But also any pagan gods believed to interact with it. The notion in Greek philosophical thought of a single god above and beyond all others goes far back as at least the fourth century B.C.The pre Christian era is a period or a time before Christian era and spread of Christianity also known as before Christianisation and it is also called before Christ (B.C). During this period the worship of or belief are in multiple deities (polytheism). Plato was the follower of the Socrates and Timaeus is one of the most important writings of Plato. Plato wrote in Timaeus one transcendent god made the world through an agent demiurge. In the ancient world Aristotle was an important philosopher and scientist. And he was known as the Alexander the great’s teacher and the student of Plato. Aristotle had the idea of god is outside of the world and the final cause of all motions in nature and he is the prime mover and unmoved mover of the universe.The founder of stoic school was Zeno of Citium a Greek philosopher, for him the transcendent being as the “one” and he tried to maintain the reverence of ancient literature that is the believe in one God. And Philo of Alexandria was immersed in two culture, Greek and Jewish. And his work was the primary important in development of the philosophical and theological foundation of Christianity. He portrayed that god’s interactions was with the physical or sense perceptible and world as being carried out by agents like Justice, Sophia and the Logos.Apostolic fathers was personally known to some of the twelve disciple of JesusChrist and apostle Paul, they are the first Christian theologians, who lived in 1st and 2nd century A.D. their writings are popular in early Christianity but not included in canon of New Testament. Theophilus of Antioch wrote to his friend, who was attract to Monotheistic view, in his second book fifteenth chapter he employed the word Trinity. And it was not intended to represent a three person God head, rather to describe god and two agents which is “Logos” and “Sophia.” This two terms as the two hands of god. “Logos” is to appear and act in physical world and “Sophia” is wisdom. Theophilus referred Jesus as an agent of god, a lesser being and he was not an early representative of trinitarian theology.Justin martyr came to Christianity with preconceived ideas, for Justin Logos is a “Power” and Justin concludes in Old Testament where god appears in son (Logos). And he explains logos is as light from sun and Jesus can be god without being the father. Clement of Rome, he is the disciple of Apostle Peter, he wrote a letter to Corinth in 96 A.D stating “Do we not have one god, one Christ, and one spirit of grace which was poured out on us and he believed in trinity. And said for as god lives, and as the Lord Jesus Christ lives and the Holy Spirit. Irenaeus of Lyon uses the term Logos as son of god. Interchangeably and he is distinguished rigidly the conception of generation though the son is begotten generated of the father, he is still like the father without beginning and eternal and some time he subordinate the son to the father. Tertullian was defending the traditional doctrine of trinity and was not originating it, the logos of doctrine of Tertullian subordinated the son to the father and says the father is the whole divine substance, and the son is a part of it and illustrates it by sun and beam. And fountain and stream. Origen of Alexandria presents the union, using the word “Homoousia” (consubstantial, or one and equal in the same essence). He indicates that father and son are respect two persons and father and son differ from each other in hypostasise for Origen the whole trinity is involved in the work of creation and in the same way that is involved in the work of salvation.The early mediaeval period is also known as early middle ages and it covers the history of Christianity from the fall of western Rome to the fall of Constantinople. In this period Arius raised a theological doctrine known as Arianism and he believed that Christ was created. And he quotes bible that Jesus at the time when during the crucifixion, he said eloi, eloi, lema sabachthani? (My god, my god, why have you forsaken me? Mark 15:34) and he claims that Christ was distinct and inferior to the father and finite. In the first ecumenical council of the Christian church met in ancient Nicaea in 325A.D to solve the problem called Arianism in this council of Nicaea, Athanasius argued, that Jesus Christ is eternal, just like the father is, it was an argument between Trinitarians against monarchianism.in this council 300 bishops gathered. This council condemned of Arius and his teaching. And the council of Constantinople assembled to unite a church that remained divided over the issue of Christ’s nature and his relationship with the father and to re-establish the doctrine. One specific area where doctrine had developed was in regard to the Holy Spirit and stated that Holy Spirit is supreme worship and equal to the father and to son.Basil of Caesarea defended the doctrine of trinity and the incarnation, he defended against the Arian heresy and the Semi-Arian heresy which both attacked the doctrine of trinity and Christ deity, were Arianism claimed that Jesus Christ is not one with the father but subordinate to him, having been created at a point in time and Semi Arianism claims that Jesus is of a “like” essence to god the father but unequal to him, both are a contradiction of scripture. Basil maintain he oneness and monarchic of god the father without subordination of the son. Basil’s trinitarian theology of one essence, one god, and one community has become the standard for eastern orthodox understanding of the Holy Trinity. In medieval period various type of Arian Christians are continued to be existed as a small group. After the council of Constantinople the main focus of Christian theology entered upon the description of Jesus Christ. Augustine of hippo accepted the Trinitarian formula which stated at the council of Constantinople. Bonaventure argued that human soul has three components like memory, intellect and will, within one soul, same as like this three aspects also correspond to the father, son, and Holy Spirit in one god. Bonaventure took this from Augustine. For Thomas Aquinas the trinity that the doctrine is not known by natural reason but only by faith and he says we can discuss about god, about what we know about him, but there still remains a mystery to us.In the reformation era the Roman Catholic rejected the sole authority of scripture and they maintained the traditional dogma of the trinity as developed by Athanasius, Augustine, Aquinas and others. In reformation period Martin Luther was an important theologian, he finds evidence for trinity in genesis 1:1 in the beginning Elohim (Plural) and Bara (singular) the heavens and the earth. For Luther three most striking candidates are speaker, spoken word, and listener. The father as the one who to comfort, the son who prays for the comforter, and the Holy Spirit who is the comfort. And John Calvin doctrine of trinity made the way for the most biblical understanding of god. His doctrine comes from the theological controversies in the historical contexts in which they lived. He supported the unity of god by mentioning “one baptism” and “one faith” and at the same time he stressed that baptism should be administered in the name of the three persons of trinity. Calvin emphasised on the importance of the divinity of Christ for the faith, and of the divinity of the Holy Spirit for communication with god the creator and god the redeemer. And he says divine nature is common to all the three person, we should not separate the person from the essence. But we should distinguish among the person while the three persons remain within the essence, and the three persons of the Godhead are consubstantial.