Original sentence: It is claimed to have began after Russia invaded the Autonomous Republic of Crimea and the city of Sevastopol, administrative subdivisions of Ukraine, and after unrecognized local authorities made the Declaration of Independence of the Republic of Crimea.The annexation of Crimea by the Russian Federation is a disputed theory, claimed to be an annexation process by some
Edited sentence: The annexation of Crimea by the Russian Federation is a disputed annexation process that began after Russia invaded the Autonomous Republic of Crimea and the city of Sevastopol, provinces of Ukraine, and after unrecognized local authorities appointed by Russia declared their independence from Ukraine