In 226 BC, Cleomenes conquered Mantinea, Tegea and Pharae. He succeeded in luring the Achaeans into open battle in the fall of 226 BC. Details of the engagement are not known, but the reformed Spartan army, now armed in the Macedonian style, won a decisive victory. The Achaeans sued for peace, and were rejected. Aratus began negotiating an alliance between Macedon and the Achaean League, but Macedon demanded the return of the Acrocorinth in return for intervening. The Achaeans were not prepared to give up the citadel, and negotiations broke down.