Although the Seljuk kingdom did not embrace the whole peninsula within its boundaries, it threatened, at first, with that terrific thrusting strength of the Mongolian conquerors, to reach out far beyond its boundaries, and to wrest from the Greeks that northwestern part of Asia Minor that was so greatly coveted. In 1080 the Seljuks were already in the extreme northwest in Bithynia, and in possession of Nicæa and Nicomedia, and were ranging the whole coast regions from Smyrna to Attalia (Adalia) as pirates. The Greeks, who were at first purely on the defensive, joined in with the Crusaders, and succeeded, after twenty years of stubborn fighting, in thrusting the Turkish conquerors back of a line which corresponds pretty closely to that of the Eskishehr-Karahissar-Akshehr railroad line of today. This was in the early part of the 12th century (1117). A second thrust by the Greeks (1139) drove them back upon their old base and center, Iconium. Western Asia Minor was thus again rescued to the Greeks and nearly forty years of quiet followed. This time was utilized by the Greek emperors to build a strong line of fortresses against possible further attacks; all strategically important points were defended by strong forts, especially the valley of the Sangarios, which formed the corridor of attack against Constantinople. Even today, as one travels over the railroad from Ismid-Eskishehr, he sees numerous, fairly well preserved ruins of these Byzantine forts which served the same purpose of border-defense as those of today in the valley of the Saal in our own land.[16] They bear Turkish names, but he who has studied into these things knows that these are only literal translations of old Greek names: Inegeul, shortened from Angelokome = Angelstown; Kupruhissar, from the Greek Gephyrokastron = Bridgefort; Karadjahissar = Greek Melangeia (Turkish, karadja = blackish). They mark, therefore, the boundary between Byzantine and Turkish history.