Those historical compositions designated as annals are exceedingly valuable sources for knowledge of the Carolingian period, none more so that the so-called Annales regni Francorum, covering an interval beginning with the death of Charles Martel and ending with the last untroubled year of Louis the Pious (741–829). For half a century (759–808) the chronicle of each year generally includes a note indicating the place where the ruler celebrated the feast of Nativity. Some years also include a reference to Easter. Thirty-seven times the allusion is to both Christmas and Easter (759–774, 777–779, 781–783, 788–792, 795–798, 800–802, 806–808); nine to Christmas only (775, 780, 784, 786, 793, 799, 803–805); four to Christmas and two Easters (776, 785, 787, 794); but none to Easter alone. The repetitive, formulaic way in which the references are introduced suggests the high festival character of celebration and observance.