On 24 February 2022, Russian tanks entered Ukraine from Belarus. Their goal was to seize Kyiv. Armoured columns moved openly, trundling through a landscape of forest and swamp. The Kremlin assumed a quick victory. The plan came dramatically unstuck in Bucha, a pleasant commuter town 15 miles from the Ukrainian capital.

A group of volunteers took to the barricades. They included a musician from an academic orchestra, a family therapist who taught Argentine tango, a recreational hunter and a gas station attendant. Over four weeks these civilians held off the mighty Russian army. They used bulldozers to build defences and warmed themselves around a fire in a bombed-out building.

As Yaroslav Hrytsak points out, no one told the volunteers to fight. Similar acts of grassroots resistance took place in other Ukrainian towns and cities in response to Russia’s sweeping invasion. “All Ukraine was seized with a spirit of initiative,” he writes. This spontaneous behaviour was in striking contrast to the passive Russians, who waited for orders.

Hrytsak is a liberal historian, intellectual and professor. He teaches at the Ukrainian Catholic University in Lviv. His book Ukraine: The Forging of a Nation is a bestseller at home and was published a few months before Vladimir Putin’s all-out attack. It puts Ukraine’s past – “permeated with violence”, but with grounds for optimism as well – in a global context.

Why, Hrytsak asks, did Ukraine fight back? He likens its struggle against Russia’s imperial machinations to the Greco-Persian wars. An alliance of democratic Greek city states successfully resisted and defeated the bigger Persian empire. Like Herodotus, the father of history who wanted to understand the causes of Greek resilience, Hrytsak roams freely, hopping from era to era.

He considers Columbus’s discovery of America in 1492, European Romanticism and the invention of the modern state in the 19th century. He also examines Ukraine’s perennial fight against domination by Moscow. Its leaders include the Cossacks; Ukrainian nationalist groups during the second world war; and a 1960s dissident movement of poets and journalists.

The book amounts to an elegant critique of chauvinist Russian thinking. And bad historiography. In 2021 Putin published a notorious “essay” that justified his imminent invasion. He argued that Ukraine was never a nation. Instead it was part of a civilisational and religious space with Russia, going back 1,000 years. According to this logic, Putin is not a brutal aggressor but a sacred restorer, of something lost and indivisible.

Previous Russian historians made similar arguments. They claimed Kyivan Rus – the ninth-century princedom, centred on Kyiv – was a precursor of today’s Russia. Hrytsak dismisses this idea. “Calling Rus a nation state is like calling a wooden abacus the first computer,” he sniffs. Kyivan Rus existed in what he calls an “anational world”. It began as a river-based trading company, centuries before the concept of statehood and borders existed.

With its fertile soil, and Black Sea coast, the region has always attracted settlers. The Scythians who appear in Herodotus’s Histories were probably proto-Iranian. Rus’s founders arrived by boat from Scandinavia. They coexisted with Slavic tribes. Next came the Ottomans. Hrytsak describes the Eurasian steppe as a multicultural highway. No single group inhabited it. Russia’s exclusive ethnic claims are “dangerous political fantasies”, he thinks.

Kyiv was founded long before Moscow and had its own distinctive political culture. This can be explained by lingering Polish influence, Hrytsak suggests. Up until the 18th century, much of modern Ukraine was a part of the Polish-Lithuanian commonwealth, a place of religious tolerance. Its gentry voted for a monarch. This consensual political system was tied to western Europe. It influenced Ukrainian identity.

The warrior Cossacks who guarded the commonwealth’s borderlands had a similar democratic culture. They chose a military leader, or hetman. After each election they pelted him with rubbish “so that he didn’t get too full of himself”, Hrytsak reports. Cossacks enjoyed autonomy. For more than 100 years they had their own state, up until 1764, when Catherine the Great folded Cossack territory into imperial Russia.

Hrytsak’s book is full of vivid metaphors. He compares Ukraine to a “bumblebee” – it shouldn’t be able to fly according to the laws of physics, but does – and to a butterfly. There is a fascinating chapter on language. Russians use the derogatory term khokhol for Ukrainians, a reference to the single lock of hair worn by steppe peoples. Ukrainians call Muscovites katsapy, or goats. These ancient insults indicate longstanding differences.

The issue of Ukrainian “separatism” – as seen by Moscow – was closely linked to publishing and language. Russian authorities repeatedly banned Ukrainian. After the 1917 revolution, the Bolsheviks allowed Ukrainian to be taught in schools. In the 1930s Stalin curtailed it again. “The policies of the Russian empire and Soviet Union are clear linguistic genocide,” Hrytsak writes, noting that “physical genocide” often accompanied it.

One reason given by Putin for his war is the need to “save” Ukraine’s Russian speakers from imagined “neo-Nazis”. Hrytsak points out that language and national identity are not necessarily connected in Ukraine, a bilingual country. Most Russian speakers consider themselves to be Ukrainian. The Russian-speaking population of Kherson protested when Russian soldiers seized the city in 2022 and rejoiced when the Ukrainian army turfed them out.

Ukraine has paid a high price for its independence. Its emergence as a sovereign state – from 1914, according to Hrytsak – coincided with a period of extraordinary bloodshed. It featured a civil war, so chaotic and confusing that it “resembles the plot of Verdi’s opera Il trovatore”. About 4.5 million Ukrainians died in the Stalin-engineered famine of 1932-3. The peasantry was broken; the intelligentsia wiped out.

Ukraine was at the centre of further violence during the second world war. Hrytsak estimates that 1.5 million of the 6 million Jews who perished in the Holocaust died in Ukraine. The Nazis executed 34,000 Jews in a single day, on 29 September 1941. There were waves of what he calls “interconnected violence”, with massacres carried out by Ukrainian partisans against Polish villages, and terrible pogroms.

Against the odds, Ukraine emerged in the late 20th and 21st centuries as a democracy. It has become, Hrytsak argues, a fully fledged civic nation. The country’s president, Volodymyr Zelenskiy, is Jewish. His new defence minister, Rustem Umerov, is a Muslim. There are “defensible” grounds for hope, the historian thinks, even as Putin continues to bombard Ukrainian homes in search of an elusive victory.

Luke Harding’s Invasion: Russia’s Bloody War and Ukraine’s Fight for Survival, shortlisted for the Orwell prize, is published by Guardian Faber

• Ukraine: The Forging of a Nation by Yaroslav Hrytsak is published by Sphere (£25). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply