Blastus a Quartodeciman Montanist at Rome about the reign of Commodus (180- 192), whom Eusebius (Hist. Eccl. v, 15) names as having at that time drawn away many from the Church by his novelties. Irenaeus wrote to him a letter On Schism ( Euseb. v, 20, 21). The appendix to Tertullian's De Prcescriptione adds to his article on the Montanists a statement that Blastus "wished secretly to introduce Judaism, saying that the Pasch must be kept only on the 14th of the month, according to the law of Moses." Pascianus, in the 4th century, speaks of him as a Greek, whom he believed to be one of the many authorities to whom the Cataphrygians (i.e. Montansists) appealed. See Gieseler, K. G. I. 1, 292 sq.; Massuet, Dis. de Iren. ii, 59; Schwegler, Montanismus, p. 242, 252.