Heraclius's reign was one of mixed fortunes. He started his reign by losing the eastern provinces, brought it to its peak by retaking them against all odds, and ended it by losing them again. It was Heraclius who first withdrew the eastern field armies into Anatolia, sowing the seeds of the Theme system, and it was he who, through depopulation and the razing of fortifications, stabilized the Anatolian frontier, which would remain largely unchanged for the next 350 years.