In these letters to Pope Gregory and Boniface, as well as an unnamed disciple, St. Columbanus expresses his greetings and concerns regarding the celebration of Easter. He argues against the practice of celebrating Easter on the 21st or 22nd of the lunar month, citing theological and historical reasons. Columbanus emphasizes the importance of adhering to the correct timing of Easter, as indicated by the vernal equinox, and critiques the acceptance of erroneous practices from Gaul. He calls for a reevaluation of these traditions, urging the Pope to correct the misunderstandings that have arisen and to uphold the sanctity of the Easter celebration.