http://en.wikipedia.org/wiki/Thomas_%C3%A0_Kempis
Thomas ā Kempis (c. 1380 - 25 July 1471) was a late Medieval
Catholic monk and the probable author of The Imitation of
Christ, which is one of the best known Christian books on
devotion. His name means, "Thomas of Kempen", his home town
and in German he is known as Thomas von Kempen. He also is
known by various spellings of his family name: Thomas
Haemerkken; Thomas Hammerlein; Thomas Hemerken, and Thomas
Hämerken.