In March 2014, the Crimean parliament held a controversial referendum in which it claimed that a large majority of voters favored joining Russia. Following this referendum, which was conducted under disputed circumstances that many international observers deemed illegitimate, the parliaments of Crimea and Russia moved swiftly to formalize this transition through the signing of an accession treaty. The signing ceremony took place at the Kremlin in Moscow, attended by Russian President Vladimir Putin and Crimean leaders, solidifying the decision made by the Crimean populace according to the official Russian narrative.

The process was rapid, with the first discussions taking place shortly after the flight of former Ukrainian President Viktor Yanukovych in February 2014. His departure was a result of protests against his government, and the instability that followed created a power vacuum in Ukraine. As tensions rose, pro-Russian sentiment in Crimea became pronounced, leading to the referendum. Internationally, the event sparked significant controversy as many nations disagreed with the legitimacy of the vote and the subsequent Russian annexation, which they viewed as a violation of international law and Ukraine's territorial integrity.

The treaty's signing was a pivotal moment that changed the geopolitical landscape in Eastern Europe, heightening tensions not only in Ukraine but also among NATO and Russia. Sanctions were subsequently imposed on Russia by multiple Western nations, and the event initiated a series of political and military conflicts that continue to affect the region today.