At first the revolt was unsuccessful, and the Wallachs and Bulgarians in alliance were obliged to retreat across the Danube (1187); but soon returning with a powerful army, in which a new tribe, the Kumani, were also represented, they succeeded in inflicting a defeat upon the Emperor Isaac (about 1193), who narrowly escaped with his life. Pressing on to Adrianople, the allies threatened to overwhelm the Eastern Empire, and the Emperor Alexius Comnenus was only too glad to conclude a peace with them (about 1199) and to recognise their independence. [Footnote 125: Pic (p. 64) says the Roumanian Wallachs were first referred to in 970, and (p. 113) first mentioned north of the Danube in 1222.] VIII. The _Wallacho-Bulgarian_ Empire lasted, according to different authors, from sixty to one hundred years, and contemporaneously with it the _Kumani_ were also dominant in part of ancient Dacia; indeed, according to some writers, Trajan's Dacia was called the land of the Kumani. The information concerning the latter is very scanty. One writer says that as the 'Uzi' they were found on the banks of the Danube at the end of the eleventh century; others say they entered Moldo-Wallachia about 1046. About 1089 they are spoken of as in Transylvania, and the period of their domination is variously stated as between these dates and 1220-1246. They were probably converted to Christianity about 1220-1223. About that time the tribe was broken up, and part of them wandered into Hungary, where they are said to have been guilty of great cruelties, and to have subsisted down to the fifteenth century. During the same period also (1200) the order of _Teutonic Knights_ had lands allotted to them in Transylvania by Andreas II. of Hungary, as well as in part of Wallachia, over which he claimed the sovereignty; but they sought to free themselves from his control, and the gift was soon withdrawn, and in 1224 they were compelled to leave the territory over which they had exercised jurisdiction. About 1247--1250 the _Knights of St. John_ also enjoyed a brief authority in some parts of Transylvania and Wallachia. The most interesting incident, of which the account has been handed down to us, in the Wallacho-Bulgarian _régime_ was the negotiation between King Joannitz, one of the first rulers (to whom reference has already been made), and Pope Innocent III. (1198-1216).