A masterpiece of illumination is the circa 1415 book "Les Très Riches Heures du" this duke
[DOC] [TLE] Janvier - Les Trs Riches Heures du duc de Berry (XVe) Frres ... [PAR] Les Tres Riches Heures Du Duc de Berry (The Book of Hours), November .... 
Illumination on vellum from the "Trs Riches Heures du Duc de ... de Berry", a 
book of prayers to be said at canonical hours created for John, Duke of Berry, .... (
Depending on who you talk to: between 1410 and 1416 and circa Limbourg 
Brothers.