Short answers, pulled from the story.
Martin Bucer (1491-1551) was a German Protestant reformer based in Strasbourg who influenced Lutheran, Reformed, and Anglican doctrines and practices. He is chiefly remembered as an early pioneer of ecumenism, working throughout his career to find common theological ground between the major Protestant factions led by Martin Luther and Huldrych Zwingli.
Bucer was the key mediator who brought the south German cities and the Wittenberg theologians to agreement in the Wittenberg Concord, signed on the 28th of May 1536. The concord addressed the disputed doctrine of the Lord's Supper by distinguishing between the unworthy who receive Christ and leaving the question of what unbelievers receive unanswered. The Swiss cities ultimately never accepted or rejected the document.
Bucer was dismissed from his position in Strasbourg on the 1st of March 1549 and left on the 5th of April, after the city's guild officials voted to accept the Augsburg Interim, an imperial decree by Charles V restoring Catholic rites throughout the Holy Roman Empire. Bucer had refused to accept the Interim despite being placed under house arrest and coerced into signing it, and he continued attacking Catholic ceremonies after his return to Strasbourg until his support base collapsed.
Bucer submitted a detailed critique of the original 1549 Book of Common Prayer to Archbishop Thomas Cranmer on the 5th of January 1551, calling for simplification of the liturgy and focusing on how ordinary congregants would worship and receive instruction. Scholars agree that while his impact on the Church of England should not be overstated, his greatest influence was on the 1552 second edition of the Prayer Book.
Bucer died in Cambridge on the 28th of February 1551 and was buried in the church of Great St Mary's. When Mary I came to the throne, she had Bucer and Paul Fagius tried posthumously for heresy; their caskets were disinterred and their remains burned along with copies of their books. On the 22nd of July 1560, Elizabeth I formally rehabilitated both reformers, and a brass plaque now marks the original location of Bucer's grave.
In summer 1538, Bucer invited John Calvin to lead a French refugee congregation in Strasbourg, beginning a long friendship between the two reformers. Many of the reforms Calvin later introduced in Geneva, including the liturgy and church organisation, were originally developed in Strasbourg under Bucer. The precise extent to which Bucer influenced Calvin remains an open question among modern scholars.