It was colonized by a people from Chalcis in Euboea, and commanded a large district called Chalcidice, in which there were thirty-two cities. Over all this tract the sway of Olynthus was considerable, and she had waged wars anciently with Athens and Sparta, and been formidable to Philip's predecessors on the throne of Macedon. Soon after Philip's accession, the Olynthians had disputes with him, which were at first accommodated, and he gratified them by the cession of Anthemus. They then joined him in a war against Athens, and he gave up to them Potidaea, which had yielded to their united arms. After the lapse of some years, during which Philip had greatly increased his power, and acquired considerable influence in Thessaly and Thrace, the Olynthians became alarmed, and began to think him too dangerous a neighbor