Martin Bucer (or Butzer) (11 November 1491 – 28 February 1551) was a Protestant reformer based in Strasbourg who influenced Lutheran, Calvinist, and Anglican doctrines and practices. Bucer's efforts to reform the church in Wissembourg resulted in his excommunication from the Roman Catholic Church, and he was forced to flee to Strasbourg. He acted as a mediator between the two leading reformers, Martin Luther and Huldrych Zwingli, who differed on the doctrine of the Eucharist. Later, Bucer sought agreement on common articles of faith such as the Tetrapolitan Confession and the Wittenberg Concord, working closely with Philip Melanchthon on the latter. Although his ministry did not lead to the formation of a new denomination, many Protestant denominations have claimed him as one of their own. He is remembered as an early pioneer of ecumenism.