The Wenceslaus Bible manuscript illumination is a supreme piece among the many splendid manuscript illuminations created at the court of the Luxembourg kings in Bohemia during the second half of the 14th century. However, these manuscript illuminations do not always have an exact dating. Thus, it is highly interesting to reconsider whether the dating of the manuscripts is actually correct, how this dating was done and on what reasons exactly it is based on. This study suggests that the Works on the Wenceslaus Bible started ten years prior to the generally accepted date, i.e. at the end of the 1370s or around the year 1380.