Five years ago today, Russia annexed Crimea. It was the first time a European state had seized territory from another since World War Two. And it was the second time in six years that Russia had carved up one of its neighbours.

In late February 2014, Russia sent its armed forces – masked and dressed in unmarked uniforms – into Crimea, a strategically-important peninsula in the south of Ukraine. Ukraine’s Russian-backed president, Viktor Yanukovych, had already fled the country after being toppled by pro-democracy demonstrators. These armed forces quickly asserted control over the peninsula. Russia swiftly organised a sham referendum in which an implausibly high 95.5% of participants voted for Crimea to join Russia.

Western leaders declared the referendum to be “illegal” and “illegitimate”, and called for “dialogue” and “de-escalation”. But while the West equivocated, Ukraine was dismembered.

With the stroke of a pen, on 18 March 2014, Putin signed a treaty absorbing Crimea into Russia. Putin claimed the annexation was about protecting the rights of ethnic Russians on the peninsula. Instead, it was about Russia’s discontent with the post-Cold War international order, which Putin had famously made clear at the Munich Security Conference in 2007. It was about Russia, resurgent and nationalistic, pushing its way back into the captive states of the former Soviet Union and reversing loses the Kremlin felt it had suffered.