in the campaign “Beginning of the Russo-Ukrainian War: Armed Invasion and Occupation of Crimea (2014)”
The legal formalization of the territory's severance: the treaty on "accession" was signed on March 18, 2014, and the law ratifying it was "Adopted by the State Duma on March 20, 2014, approved by the Federation Council on March 21, 2014"[1].