Mertens, Martins, or Martini, the Printer

Can any of your correspondents inform me what was really the surname of Theodoric Mertens, Martins, or Martini, the printer of Louvain, and who was a friend of Erasmus? In a small volume of his, now before me, printed in 1517, the colophon gives: "Lovanii apud Theodoricum Martinum anno MDXVII mense April;" while, on the reverse of *the same leaf*, is a wooden block, of his device, occupying the whole page, and beneath it are inscribed the words "Theodoricus Martini." This appears to put Mertens out of the question.