Mediana is a term peculiar to Roman liturgy and is applied to the fifth Sunday in Lent, to the Wednesday and Saturday which precede this Sunday, and to the week embracing these three days. The term first occurs in a letter of Pope Gelasius, written in 494, in which he says that ordinations of priests and deacons should only be performed at certain seasons on Saturday evening, namely the fasts of the fourth, seventh and tenth months, which are the original Embertides, on the first Saturday in Lent, which is in the fourth and later Embertide, and on the Saturday medianae quadragesimae. The term occurs again in the next century when Pope Pelagius I (556–561) appointed this mediana septimana paschae as a season for ordinations. The text of Gelasius is quoted in the Liber Diurnus, of which the earliest manuscript dates from the seventh to the eighth century; in a letter of Gregory II of 715; and in the eleventh Canon of the Roman Council of 743.