Berke – Hulagu war The Berke – Hulagu war was a civil war in the Mongol Empire which fought between two Mongol leaders : Berke Khan of the Golden Horde , and Hulagu Khan of the Ilkhanate . It was fought mostly in the Caucasus mountains area in the 1260s after the destruction of Baghdad in 1258 . The war marked a key moment in the fragmentation of the Mongol Empire after the death of the Great Khan Mongke . Background . In 1252 , Berke converted to Islam , and in 1257 he assumed power in the Golden Horde after the death of Ulaghchi . Like his brother Batu , he was loyal to the Great Khan Mongke . Although aware of Berke ' s conversion to Islam , Hulagu , after conquering Persia , destroyed Baghdad in 1258 , added Iraq to the Mongol Empire , advanced towards Syria and Mamluk Sultanate , and began a war of attrition against the Mamluk Sultanate . Berke became enraged with Hulagu ' s rampage through Muslim lands , and as a preparatory step , directed his nephew Nogai Khan to raid Poland in 1259 in order to collect booty to finance a war . Several Polish cities were plundered , including Kraków and Sandomierz . Berke then struck an alliance with the Mamluk Sultan Qutuz and later Sultan Baibars of Egypt . That same year , Mongke died in a military campaign in China . Muslim historian Rashid al Din quoted Berke Khan as sending the following message to Mongke Khan , protesting the attack on Baghdad , ( not knowing Mongke had died in China ) . The war . In 1260 Hulagu ' s lieutenants in the Middle East lost the Battle of Ain Jalut to the Mamluks while Hulagu was in Mongolia to participate in the succession of a new Great Khan following the death of Mongke . Upon hearing the news , Hulagu began preparing to avenge the defeat . Two years later he returned to his lands in Persia , but was distracted and prevented from dealing with the Mamluks when Berke carried through on the threat to war against his cousin so as to avenge the sack of Baghdad . Berke again unleashed Nogai Khan to launch a series of raids - this time multiple reconnaissances in force in the Caucasus region - which drew Hulagu north with the bulk of his forces . Berke also dispatched Negudar to eastern Afghanistan and Ghazni , recovering lands under Il Khanate control . Hulagu was loyal to his brother Kublai , but clashes with their cousin Berke , the ruler of the Golden Horde in the northwestern part of the Empire , began in 1262 . The suspicious deaths of Jochid princes in Hulagu ' s service , unequal distribution of war booties and Hulagu ' s massacres of the Muslims increased the anger of Berke , who considered supporting a rebellion of the Georgian Kingdom against Hulagu ' s rule in 1259 - 1260 . Berke also forged an alliance with the Egyptian Mamluks against Hulagu , and supported Kublai ' s rival claimant , Ariqboke . Kublai dispatched an army under Abaqa to attack the Golden Horde , while Ariqboke sent Nogai to invade the Ilkhanate ; both sides suffered disastrous defeats . Arikboqe surrendered to Kublai at Shangdu on August 21 , 1264 , after which the rulers of the Golden Horde and Chagatai Khanate acknowledged the reality of Kublai ' s victory and rule , after which Kublai began preparations for his conquest of the Song Dynasty . When the Byzantine Empire , the ally of the Ilkhanate , captured Egyptian envoys , Berke sent an army through his vassal Bulgaria , prompting the release of the envoys and the Seljuq Sultan Kaykaus II . He tried to raise civil unrest in Anatolia using Kaykawus but failed . In the new official version of the family history , Kublai Khan refused to write Berke ' s name as the khan of Golden Horde for his support to Arikboke and wars with Hulagu , however , Jochi ' s family was fully recognized as legitimate family members . Kublai Khan also reinforced Hulagu with 30 , 000 young Mongols in order to stabilize the political crises in western khanates . As soon as Hulagu died on the 8th of February , 1264 , Berke marched to cross near Tiflis , but he died on the way . Within a few months of these deaths , Alghu Khan of the Chagatai Khanate died too . Nevertheless , this sudden vacuum of power relieved Kublai ' s control over the western khanates somehow . Aftermath . This was the second open war between Mongols , shortly after the beginning of the war between Kublai Khan and Ariq Böke . Before that there had been tensions between Batu and Güyük that could have erupted into an open war , but the premature death of the latter averted hostilities . Together with the war between Kublai Khan and Ariq Böke , Berke and Hulagu set the precedents that was repeated in the form of further wars between Mongol khanates , such as the conflicts between Abaqa and Barak in 1270 , Kaidu and Kublai Khan in the 1270s and 1280s , Toqta and Nogai in the late 1290s , and the war between Duwa and Chapar in the early 14th century . This war , along with the second raid against Poland , also marked the rise of Nogai Khan in the Golden Horde . After Berke ' s death he became ever more powerful , and became a kingmaker in the Golden Horde .