The chronological diffficultics which perplex the residence of Athanasius at Rome are strenuously agitated by Valesius (Observat. ad Calcem, tom. ii.; Hist. Eccles. 1. i. c. 1-5) and Tillemont (Mem. Eccles. tom. viii. p. 674, etc.). I have followed the simple hypothesis of Valesius, who allows only one journey after the intrusion of Gregory.