Appian of Alexandria Civil Wars 4.13.105

[105] Thus Brutus and Cassius by an astounding act of audacity advanced to Philippi, where Tillius also disembarked, and the whole army was there assembled. Philippi is a city that was formerly called Datus, and before that Crenides, because there are many springs ¹ bubbling around a hill there. Philip fortified it because he considered it an excellent stronghold against the Thracians, and named it from himself, Philippi. It is situated on a precipitous hill and its size is exactly that of the summit of the hill. There are woods on the north through which Rhascupolis led the army of Brutus and Cassius. On the south is a marsh extending to the sea. On the east are the gorges of the Sapaeans and Corpileans, and on the west a very fertile and beautiful plain extending to the towns of Murcinus and Drabiscus and the river Strymon, about 350 stades. Here it is said that Cora was carried off while gathering flowers, and here is the river Zygactes, in crossing which they say that the yoke of the god’s chariot was broken, from which circumstance the river received its name. ² The plain slopes downward so that movement is easy to those descending from Philippi, but toilsome to those going up from Amphipolis.