foiled any attempts of allied landing on the Taman Peninsula, whilst the 2nd and 5th plastun battalions took part in the Defence of Sevastopol. In the land they left behind, the Buh Cossacks were able to provide a strong buffer from the Danubian Sich. After the Russo-Turkish War (1828–1829) most of the Danube Cossacks officially turned themselves over and under amnesty were resettled between the Mariupol and Berdyansk, forming the Azov Cossack Host. Expansion As the years went by, the Black Sea Cossacks continued its systematic penetrations into the mountainous regions of the Northern Caucasus. Taking an active part in the finale of the Russian conquest of the Northern Caucasus, they settled the regions each time these were conquered. To aid them, a total of 70 thousand additional ex-Zaporozhians from the Bug, Yekaterinoslav, and finally the Azov Cossack Host migrated there in the mid 19th century. All three of the former were necessary to be removed to vacate space for the colonisation of New Russia, and with the increasing weakness of the Ottoman Empire as well as the formation of independent buffer states in the Balkans, the need for further Cossack presence had ended. They made the migration to the Kuban in 1860. Separating the ethnic Ukrainian Black Sea Cossacks from the Caucasian mountain tribes were the Caucasus Line Cossack Host, ethnic Russian Cossacks from the Don region. Although both groups lived in the general Kuban region, they did not integrate with each other. Apogee of the Kuban Host The new Host grew to be the second largest in Russia. The Kuban Cossacks continued to make an active part in the Russian affairs of the 19th century starting from the finale of the Russian-Circassian War which ceased shortly after the hosts' formation. A small group took part in the 1873 conquest that brought the Khanate of Khiva under Russian control. Their largest military campaign was the Russo-Turkish War (1877–1878), on both the Balkan and the Caucasus fronts. The latter in particular was a strong contribution as the Kuban Cossacks made 90% of the Russian cavalry. Famous achievements in the numerous Battles of Shipka, the defence of Bayazet and finally, in decisive and victorious Battle of Kars where the Cossacks were the first to enter. Three Kuban Cossack regiments took part in the storming of Geok Tepe in Turkmenistan in 1881. During the Russo-Japanese War (1904–1905), the host mobilised six cavalry