state authority did not extend, and often took part in rebellions which were constantly breaking out in Ukraine. Another problem for the imperial Russian government was the Cossacks' resistance to colonization of lands the government considered theirs. In 1775, after numerous attacks on Serbian colonisers, the Russian Empress Catherine the Great had Grigory Potemkin destroy the Zaporozhian Host. The operation was carried out by General Pyotr Tekeli. The Zaporozhians scattered; some (five thousand men or 30% of the host) fled to the Ottoman-controlled Danube area. Others joined the Imperial Russian Husar and Dragoon regiments, while most turned to local farming and trade. A decade later, the Russian administration was forced to reconsider its decision, with the escalation of tension with the Ottoman Empire. In 1778 the Turkish sultan offered the exiled Zaporozhians the chance to build a new Danubian Sich. Potemkin suggested that the former commanders Antin Holovaty, Zakhary Chepiha and Sydir Bily round the former Cossacks into a Host of the loyal Zaporozhians in 1787. The new host played a crucial role in the Russo-Turkish War (1787–1792), and for their loyalty and service the Russian Empress rewarded them with eternal use of the Kuban, then inhabited by Nogai remnants, and in the cause of the Caucasus War a crucial progress in further pushing the Russian line into Circassia. Renamed the Black Sea Cossack Host, a total of 25,000 men made the migration in 1792-93. On the Russian frontier (1777–1860) During the Russo-Turkish War (1768-1774), the Don Cossacks on the Khopyor River took part in the campaign, and in 1770 – then numbering four settlements – requested to form a regiment. Owing to their service in the war, on 6 October 1774 Catherine the Great issued a manifesto granting their request. The end of the war and the Treaty of Küçük Kaynarca brought Russia's frontiers south from the Kuban River's entry into the Azov Sea along its right bank and right to the bend of the Terek River. This created a 500-verst undefended border, and in the summer of 1777 the Khopyor regiment – in addition to the remnants of the Volga Cossacks and a Vladimir Dragoon regiment – were re-settled in the Northern Caucasus to build the Azov-Mozdok defence line. This marked the start of the Caucasus War, which would continue for almost 90 years. The Khopyor regiment was responsible for the western flank of the line. In 1778-1782,