It was not till the Seljuk kingdom was finally extinguished, in or about 1300 A.D. that Osman assumed at Yenishehr the style and title of a sultan. Acknowledged from Afium Kara Hissar, in northern Phrygia, to the Bithynian coast of the Marmora, beside whose waters his standards had already been displayed, he lived on to see Brusa fall to his son Orkhan, in 1326, and become the new capital. Though Nicaea still held out, Osman died virtual lord of the Asiatic Greeks; and marrying his son to a Christian girl, the famous Nilufer, after whom the river of Brusa is still named, he laid on Christian foundations the strength of his dynasty and his state. The first regiment of professional Ottoman soldiery was recruited by him and embodied later by Orkhan, his son, from Greek and other Christian-born youths, who, forced to apostatize, were educated as Imperial slaves in imitation of the Mamelukes, constituted more than a century earlier in Egypt, and now masters where they had been bondmen. It is not indeed for nothing that Osman’s latest successor, and all who hold by him, distinguish themselves from other peoples by his name. They are Osmanlis (or by a European use of the more correct form Othman, ‘Ottomans’), because they derived their being as a nation and derive their national strength, not so much from central Asia as from the blend of Turk and Greek which Osman promoted among his people. This Greek strain has often been reinforced since his day and mingled with other Caucasian strains. It was left to Orkhan to round off this Turco-Grecian realm in Byzantine Asia by the capture first of Ismid (Nicomedia) and then of Isnik (Nicaea); and with this last acquisition the nucleus of a self-sufficient sovereign state was complete. After the peaceful absorption of the emirate of Karasi, which added west central Asia Minor almost as far south as the Hermus, the Osmanli ruled in 1338 a dominion of greater area than that of the Greek emperor, whose capital and coasts now looked across to Ottoman shores all the way from the Bosphorus to the Hellespont. 2 _Expansion of the Osmanli Kingdom_ If the new state was to expand by conquest, its line of advance was already foreshadowed. For the present, it could hardly break back into Asia Minor, occupied as this was by Moslem principalities sanctioned by the same tradition as itself, namely, the prestige of the Seljuks. To attack these would be to sin against Islam. But in front lay a rich but weak Christian state, the centre of the civilization to which the popular element in the Osmanli society belonged. As inevitably as the state of Nicaea had desired, won, and transferred itself to, Constantinople, so did the Osmanli state of Brusa yearn towards the same goal; and it needed no invitation from a Greek to dispose an Ottoman sultan to push over to the European shore.