Conrad of Hirsau (c.1070 – c.1150) created the famous Trees of Vices and Virtues in De fructu carnis et spiritus, which he prepared before 1133 for illiterate lay brothers. This investigation provides an edition and translation of that work and defines its influential images. It also discovers the convoluted process through which Conrad developed that work into the Speculum virginum c.1140 – 1150 for religious women. This study reveals that Conrad composed that work for his two young women relatives who had entered the Andernach convent, that the autograph manuscript is British Library Arundel 44, and that Conrad himself rendered its numerous innovative pictures.