Early life and career
Beza studied law in Orleans from 1535-39. After receiving his degree, he set up his own law practice. During this time, in 1548, Beza published Juvenilia, "a volume of amorous verse" which gave him a reputation as a leader in Latin poetry.
Conversion and involvement in the Reformation
After falling seriously ill, Beza was saved and became a Protestant Christian. In 1548 he travelled to Geneva, joined John Calvin, and became very involved in the Reformation in the area. Beza served as a professor of Greek in Lausanne from 1549–58, and one of his more notable actions during time was to write De haereticis a civili magistratu puniendis in 1554, which defended the conduct of Calvin and the Geneva government in the burning of the Michael Servetus, a heretic who denied the Trinity.
Leader of the Reformation in Geneva
After Calvin died in 1564, Beza succeeded him as the leader of the Reformation in the city. Beza became the chief pastor and the chair of theology, positions he would hold for the rest of his life.
During this time, Beza wrote numerous sermons, commentaries, and other texts. Beza played a large role in the formation of Calvinist theology; while he agreed with John Calvin on the vast majority of issues, he changed Calvinist theological doctrine, after the St. Bartholomew's Day Massacre, from being obedient to every civil authority to being able to justly revolt if that authority was tyrannical.
Other notable actions of Beza include his Greek and Latin editions of the New Testament, which played a large role in the writing of the Geneva Bible and the King James Version. Additionally, Beza donated the Codex Bezae, an important 5th Century Greek and Latin manuscript of the Gospels and the Acts of the Apostles, to the University of Cambridge.
While Beza is known for his role as a scholar, he, like many other Reformers, also worked hard as a pastor, pastoring for almost 40 years and giving biblically sound sermons.