Hippolyte Delehaye, S.J., was a Belgian Jesuit who was a hagiographical scholar and an outstanding member of the Society of Bollandists.
Hippolyte Delehaye
A hagiography is a biography of a saint or an ecclesiastical leader, as well as, by extension, an adulatory and idealized biography of a preacher, priest, founder, saint, monk, nun or icon in any of the world's religions. Early Christian hagiographies might consist of a biography or vita, a description of the saint's deeds or miracles, an account of the saint's martyrdom, or be a combination of these.
Page from the Vita Sancti Martini by Sulpicius Severus
Calendar entries for 1 and 2 January of the Martyrology of Oengus.
Example of Greek Orthodox visual hagiography. This is one of the best known surviving Byzantine mosaics in Hagia Sophia – Christ Pantocrator flanked by the Virgin Mary and John the Baptist made in the 12th century.