Original sentence: Currently, the Crimean Peninsula is administered by the Russian Federation as the Crimean Federal District.Most developments apply to the Crimean Peninsula, a multi-ethnic region which untill February 2014 was administered by Ukraine as the Autonomous Republic of Crimea and the administratively separate municipality of Sevastopol, both are populated by an ethnic Russian majority and a minority of both ethnic Ukrainians and Crimean Tatars
Edited sentence: Most developments apply to the Crimean Peninsula, a multi-ethnic region of Ukraine composed of the former Autonomous Republic of Crimea and the administratively separate municipality of Sevastopol; both are populated by an ethnic Russian majority and a minority of both ethnic Ukrainians and Crimean Tatars