Telesphorus

Pope Telesphorus (d. c. 137) was the eighth Bishop of Rome and, according to multiple early sources including Irenaeus and Eusebius, the only second-century pope whose martyrdom is historically attested with confidence. Of Greek ancestry, born in Thurii (modern Calabria), Telesphorus was reportedly an anchorite (hermit monk) before assuming the office of bishop. His pontificate occurred during the reigns of Emperors Hadrian and Antoninus Pius — a period of relative tolerance interrupted by sporadic local persecution. Telesphorus is traditionally credited with establishing the practice of celebrating the Christmas midnight Mass (the 'Mass of the Angels') and introducing the singing of the Gloria in Excelsis Deo at the Christmas liturgy. While these attributions may be anachronistic, they reflect the Church's memory of his contribution to the development of Christian worship.