About the time of his decennial celebration, 3028 his sons Crispus and Constantine, and Licinius, son of Licinius, were made Cæsars. The peace between the emperors continued during the whole of this period. There was more or less fighting with the frontier tribes, Crispus, e.g., defeating the Franks in 320 (Naz. Paneg. c. 3. 17?), but the main interest of the period does not lie in its wars. It was a period of legislation and internal improvement (cf. Laws of 319, 320, 321, collected in Clinton, 1, p. 9; also De Broglie, I. 1, 296–97). Early in the period he was at Milan, where the Donatist matter, which had been dragging along since 311, came up for final settlement (cf. note, above). He was also at one time or another at Arles and at Rome, but the latter and greater part of the period was spent mainly in Dacia and Pannonia (cf. Laws, as above). The close of his fifteen years was celebrated somewhat prematurely at Rome, in the absence of Constantine, by the oration of Nazarius (cf. Naz. Paneg.).