Derived from Latin sedulus "zealous, diligent, industrious". This name was borne by Coelius Sedulius, a Christian poet of the first half of the 5th century.
Latinization of Siadhal. This name was borne by Sedulius Scottus (sometimes called Sedulius the Younger, to distinguish him from Coelius Sedulius; fl. 840–860), an Irish teacher, Latin grammarian, and scriptural commentator who lived in the 9th century. During the reign of the Emperor Lothair (840–855), he was one of a colony of Irish teachers at Liège.