 His books on the Lord's Supper were published with the co-operation of the Swiss Brethren in Zürich, specifically Felix Mantz and probably Andreas Castelberg, as well as Karlstadt's brother-in-law, Gerhard Westerburg of Cologne, who baptized over 2,000 adults in his swimming pool.Karlstadt's influence on Protestantism in general included the abolition of mandatory celibacy (he married more than three years before Luther, and published several writings on the subject, both in Latin and German).As to images and liturgy, he influenced Zwingli and the Anabaptists directly, and, indirectly, the Baptists and Presbyterian Protestants.