Mantz, Felix a Baptist martyr of the early part of the 16th century, and a leader of the Reformation in Germany, was a native of Zurich. In 1519 he studied Hebrew with Zwingle, under Carlstadt, and was intimate with that reformer, and also with Myconius, Capito, and other leaders of the Swiss Reformation. About 1522 he objected openly to the doctrine of infant baptism, to the tithes, usury, and other peculiarities of the Romish Church, and thus failing to harmonize with the opinions of Zwingle, he was led to a separation from the party of that reformer, and became connected with the Baptists. In 1523 he preached publicly on the subject of baptism. In the three disputes held at Zurich in 1525, Mantz appears to have taken part, and after that of March was thrown into prison, from which, however, he escaped. He afterwards preached in different parts of Switzerland; in 1526 was imprisoned in the tower of Wellenberg, on the charge of baptizing contrary to the prohibitory edict of the magistrates of Zurich, and, refusing to recant, was condemned, and drowned in January, 1527. See Brown, Baptist Martyrs, p. 49 (Amer. Bap. Pub. Soec. Phila.).