Under the reforms of Diocletian, its northern and southern parts were split off to form the southern part of the province of Paphlagonia and the province of Lycaonia, respectively. In ca. 398, during the reign of Arcadius, it was divided in two provinces, Galatia Prima and Galatia Secunda or Salutaris. Galatia Prima covered the northeastern part of the old province, retaining Ancyra as its capital, and was headed by a consularis, while Salutaris comprised the southwestern half of the old province, and was headed by a praeses with seat at Pessinus. Both provinces were part of the Diocese of Pontus. The two provinces were briefly reunited in 536-548 under Justinian I. Although the area was eventually incorporated in the new thema of Anatolikon in the latter half of the 7th century, traces of the old provincial administration survived until the early 8th century.