The authorship of the work entitled Dc Imitatione Christi, has afforded as much controversy as the author of Letters of Junius. In 1604, a Spanish Jesuit discovered a manuscript copy by the Abbot John Gersen or Gesen; and since then three competitors have had angry and wordy defenders, viz. Thomas à Kempis, J. Charlier de Gerson, Chancellor of the University of Paris, and the Abbot Gersen. M. Malou gives his verdict in favour of the first.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894