The name was said to have signified 'the country of Balar', and to have been given at first to the lands about the mouths of Sirion that faced the Isle of Balar. Later the name spread to include all the ancient coast of the Northwest of Middle-earth south of the Firth of Drengist, and all the inner lands south of Hithlum and eastwards to the feet of the Blue Mountains, divided by the river Sirion into East and West Beleriand. Beleriand was broken in the turmoils at the end of the First Age, and invaded by the sea, so that only Ossiriand (Lindon) remained. Passim; see especially 142-8, 313, 354-5