During Ptolemy II's reign, the material and literary splendour of the Alexandrian court was at its height. He promoted the Museum and Library of Alexandria. In addition to Egypt, Ptolemy's empire encompassed much of the Aegean and Levant. He pursued an aggressive and expansionist foreign policy with mixed success. From 275 to 271 BC, he led the Ptolemaic Kingdom against the rival Seleucid Empire in the First Syrian War and extended Ptolemaic power into Cilicia and Caria, but lost control of Cyrenaica after the defection of his half-brother Magas. In the Chremonidean War (c. 267-261 BC), Ptolemy confronted Antigonid Macedonia for control of the Aegean and suffered serious setbacks. This was followed by a Second Syrian War (260-253 BC) against the Seleucid empire, in which many of the gains from the first war were lost.