Peter Martyr Vermigli was an Italian-born Calvinist theologian. His early work as a reformer in Catholic Italy and his decision to flee for Protestant northern Europe influenced many other Italians to convert and flee as well. In England, he influenced the Edwardian Reformation, including the Eucharistic service of the 1552 Book of Common Prayer. He was considered an authority on the Eucharist among the Calvinist churches, and engaged in controversies on the subject by writing treatises. Vermigli's Loci Communes, a compilation of excerpts from his biblical commentaries organised by the topics of systematic theology, became a standard Calvinist theological textbook.
Born in Florence, Vermigli entered a religious order and was appointed to influential posts as abbot and prior. He came in contact with leaders of the Italian spirituali reform movement, and read Protestant theologians such as Martin Bucer and Ulrich Zwingli. Through reading these works and studying the Bible and the Church Fathers, he came to accept Protestant beliefs about salvation and the Eucharist.