During the first 22 years of his reign Thutmose III was overshadowed by his aunt Hatshepsut, wife of Thutmose II, who had herself declared regent in 1503. When she died in 1482, he promptly mobilized the army and defeated a coalition of Syrian and Palestinian enemies near Megiddo, gaining nearly all of Syria for his empire. Further successes followed, culminating in the defeat of the powerful Mitanni beyond the Euphrates. He extended Egyptian rule in Nubia, but generally he concentrated on the administration of his lands. The thriving prosperity of his reign was reflected in much new building at Karnak.