people withdrew to the mountains. Samuel left part of the army at the foot of the mountains and led the remaining soldiers to besiege the coastal fortress of Ulcinj. In an effort to prevent bloodshed, he asked Jovan Vladimir to surrender. After the prince refused, some Serb nobles offered their services to the Bulgarians and, when it became clear that further resistance was fruitless, the Serbs surrendered. Jovan Vladimir was exiled to Samuel's palaces in Prespa. The Bulgarian troops proceeded to pass through Dalmatia, taking control of Kotor and journeying to Dubrovnik. Although they failed to take Dubrovnik, they devastated the surrounding villages. The Bulgarian army then attacked Croatia in support of the rebel princes Krešimir III and Gojslav and advanced northwest as far as Split, Trogir and Zadar, then northeast through Bosnia and Raška and returned to Bulgaria. This Croato-Bulgarian War allowed Samuel to install vassal monarchs in Croatia. Samuel's relative Kosara fell in love with the captive Jovan Vladimir. The couple married after gaining Samuel's approval, and Jovan returned to his lands as a Bulgarian official along with his uncle Dragomir, whom Samuel trusted. Meanwhile, Princess Miroslava fell in love with the Byzantine noble captive Ashot, son of Gregorios Taronites, the dead governor of Thessaloniki, and threatened to commit suicide if she was not allowed to marry him. Samuel conceded and appointed Ashot governor of Dyrrhachium. Samuel also sealed an alliance with the Magyars when his eldest son and heir, Gavril Radomir, married the daughter of the Hungarian Grand Prince Géza. Advance of the Byzantines The beginning of the new millennium saw a turn in the course of Byzantine-Bulgarian warfare. Basil II had amassed an army larger and stronger than that of the Bulgarians: determined to definitively conquer Bulgaria, he moved much of the battle-seasoned military forces from the eastern campaigns against the Arabs to the BalkansR. V. Rozen, Emperor Basil the Bulgar-slayer (Imperator Vasiliy Bolgaroboytsa, Император Василий Болгаробойца), p. 34. and Samuel was forced to defend rather than attack. In 1001, Basil II sent a large army under the patrician Theodorokanos and Nikephoros Xiphias to the north of the Balkan Mountains to seize the main Bulgarian fortresses in the area. The Byzantine troops recaptured Preslav and Pliska, putting north-eastern Bulgaria once again under Byzantine rule. The following year, they struck in the opposite direction, marching through Thessaloniki to tear off Thessaly and the southernmost parts of the