Lokris (Locris) consisted of a narrow strip upon the east coast of central Greece, from the pass of Thermopylae to the mouth of the river Cephissus. The northern frontier town was Alpeni, which bordered upon the Malians, and the southern frontier town was Larymna, which at a later time belonged to Boeotia. On the west, the Locrians were separated from Phocis and Boeotia by a range of mountains, extending from Mount Oeta and running parallel to the coast. The Lokrians, however, did not inhabit this coast continuously, but were divided by a narrow slip of Phokis, which extended to the Euboean sea, and contained the Phokian seaport town of Daphnus. Lokrians north of Daphnus were called Epicnemidii, from Mount Cnemis; and to the south were named Opuntii, from Opus, their principal city. Lokris is mountainous but there are several fruitful valleys, and the fertility of the whole of the Lokrian coast is praised both by ancient and modern observers. The cities and towns of the Lokri Epicnemidii, along the coast from north to south, were: Alpenus, Nicaea, Scarphe (Scarpheia), Thronium, Cnemis (Cnemides), more inland, Tarphe later Pharygae, and Augeiae. The cities and towns of the Lokri Opuntii, along the coast from north to south, were: Alope, Kynos, Opus, Halae, Larymna which later belonged to Boeotia, more inland, Calliarus, Naryx, and Corseia. Lokrians are mentioned by Homer, who describes them as following Ajax, the son of Oïleus, to the Trojan War in forty ships. In the Persian War the Opuntian Lokrians fought with Leonidas at the Battle of Thermopylae, and also sent seven ships to the Greek fleet. The Lokrians fought on the side of Sparta in the Peloponnesian War.