On Tuesday, after months of discussions, Finland officially became the 31st member of the North Atlantic Treaty Organisation (NATO).

The Scandinavian nation was officially announced as a NATO member at a formal ceremony at the organisation’s headquarters in Brussels.

NATO Secretary General Jens Stoltenberg and U.S. Secretary of State Antony Blinken attended the ceremony as the Minister for Foreign Affairs, Pekka Haavisto, established Finland’s accession.

The move ends an era of military non-alignment for Finland and guarantees military support from all NATO members should they be invaded.

Finland’s decision comes just over one year after Russia invaded Ukraine. Ukraine, a non-NATO member, has struggled to defend its sovereign territory from the Russian onslaught. Finland has a large land border with Russia, making it suspectable to a potential invasion from Russia. Finland, like Ukraine, was once part of the Russian Empire. Putin has been vocal about his goal of recapturing lost territory from the Russian empire. As such, Finland was left in a vulnerable position without a military alliance.