But all this Bulgarian prosperity had a serious check when Simeon died in 927 and the Czar Peter ascended the throne. Scarcely was Simeon cold in his grave before internal struggles had begun, owing to the jealousies of some of the nobles and their spirit of adventure. The boyars (knights) of Bulgaria had always had great authority. Now they took advantage of a monarch who was more suited for the cloister than the Court to revive old pretensions to independent power. Czar Peter turned to the Greek Empire for help, and sought to strengthen his position at home by a marriage with the grand-daughter of the Emperor Romanus Lecapenus. That policy served until a vigorous Greek Emperor came to the throne at Constantinople and set himself to avenge the victories of Simeon. The Greek Emperor called in the aid of the northern Russians against their kinsfolk the Bulgarian Slavs. There followed a typical Balkan year of war. The Russians succeeded only too well against the Bulgarians, and then the Greeks, in fear, joined with the Bulgarians to resist their further progress. Then the Servians took advantage of the war to shake off the Bulgarian suzerainty and regain their independence. An opposition party in Bulgaria, disgusted with the misfortunes which had befallen their country under Peter, added to these misfortunes by a revolt, and seceded to found the kingdom of Western Bulgaria under the boyar Shishman Mokar (963). To add to the troubles of the Balkans, the Bogomil heresy appeared, dividing further the strength of the Bulgarian nation. The Bogomils were the first of a long series of Slavonic fanatics, ancestors in spirit of the Doukhobors, the Stundists, and the Tolstoyans of our days, preaching the hermit life as the only truly holy one, forbidding marriage as well as war and the eating of meat. It was with such dissensions among the Christian states of the Balkans that the way was prepared for the coming of the Turk to the Peninsula.