So, violence on the streets in Catalonia and perhaps secession from Spain? A few thousand kilometres to the east and the Kurds are in the process of doing just that from Iraq. Clearly, many of the compromises and land (and resource) grabs that followed on the wars of the past two centuries didn’t work. Indeed, in many cases you could say that they created the wretched world we now inhabit and the only people to truly benefit were arms manufacturers and oil dealers.

When the Great War ended, the Austro-Hungarian, Ottoman and Russian empires were no more. The arbitrary lines drawn on the world’s map created myriad new “countries”, many of which made no sense at all to those living on the ground, especially, but by no means exclusively, in the Middle East, where the divvy-up haunts us yet.

Even the winners lost. Whose flag fluttered over what square was a sideshow. The deaths of so many millions of young men in the trenches and margins utterly changed the demographies of the war-weary states. Migration rebuilt labour forces. Women emerged from the shadows into work and public life. And so on.

The course of the Great War created opportunities for revolutionaries too. We’ve been marking the centenary of the Easter Rising for the past 18 months. A year later, another revolutionary movement proved more immediately successful in Russia. There, agitation ploughed fertile ground. An archaic and autocratic society hadn’t adapted at all as the 19th century ran its course.

During the Great War the Russian economy crumbled. There were food riots and demonstrations where workers were joined by mutinous and disillusioned soldiers. The incompetent conduct of the war also rankled. After weeks of chaos Tsar Nicholas II abdicated, bringing the Romanov dynasty to an end in February 1917.

But this was just the opening act. Chaos ensued with various factions competing for control, even as the war continued. Urban workers organised themselves into councils known as soviets. Mass strike actions took place right across Russia and workers took control of many factories. Over 4,000 peasant uprisings took place.

The Bolsheviks, led by Lenin, set up a revolutionary military committee inside the workers’ council (soviet) in Petrograd, then the capital, and now St Petersburg. This was led by Leon Trotsky. Like the Irish revolutionaries in 1916 they set out to occupy strategic locations through the city. On October 26th 1917, they stormed the Winter Palace and the communist era began.

Apparently the takeover was relatively bloodless. As we in Ireland might ruefully recognise, events and individual contributions were much exaggerated in their retelling. But blood was certainly shed in the days and weeks that followed, with battles for control of ruling bodies as well as towns and cities, secessionary movements and declarations of independence in Ukraine, Estonia and Georgia...

The civil war that followed lasted from 1918 to 1922. The Bolshevik Red Army fought the White Army, itself a melange of incompatible forces only united by their opposition to the Reds. Up to 10 foreign powers became involved as well, including the United Kingdom, France, Italy, the US and Japan.

The mess and muddle of this war, the myriad contending factions, its horrors both little and large, the tedium and futility and sudden baleful violence, the grotesque and the gory, the inglorious and often random encounters between soldiers and peasants and trailing families, brutishness and tenderness side by side, the importance of a good horse, the occasional joke... all are brilliantly captured by the Russian Jewish writer Isaac Babel in his book Red Cavalry (Pushkin Press). It’s a long way from glory, that’s for sure.

By the time the Red Army finally prevailed Finland, Estonia, Latvia, Lithuania and Poland were independent states and a combination of battlefield deaths, summary executions, the Red Terror and drought, famine and disease had accounted for between seven and 12 million people. As the war petered out in 1922, Lenin suffered several strokes that ended his career and he died in 1924. Then came Stalin (whose name means “man of the steel hand”…) The latter’s opponents were isolated and an era of violent suppression, intrigues and purges began. Isaac Babel was among those lost, murdered in a purge in 1940.

Trotsky was exiled to Turkey but he continued his opposition to Stalin and the direction the USSR had taken. He later went to Mexico where, from 1937-1939 he and his wife lived in the home of communist Mexican painters Diego Rivera and Frida Kahlo, with whom Trotsky had an affair. He was murdered with an ice pick in Mexico in 1940 by Ramon Mercador, a Spanish born Soviet agent.

The assassin spent 20 years in a Mexican jail. His Soviet handlers made sure he was well treated there, sending money every week and arranging a girlfriend, a Mexican starlet named Roquella whom he married and brought to the Order of Lenin.

It would be tempting to characterise it all as a vast communist Game Of Thrones – how Moscow reacted after his release, and to lampoon the ultra-ratty ideological battles between Stalinists, Trots and Maoists. On which, see The Life Of Brian. But the monstrous violence of Stalin’s USSR was essentially a bigger and more brutishly impersonal version of what had been the European norm for many centuries.

In its utopian iteration, communism was supposed to see the wretched inherit the earth. But instead it’s a wretched earth that we have inherited (and perhaps created). In most respects, much of our world would make little sense to those Bolsheviks a century ago. But yet, they’d get a lot of it, especially that the rich keep getting richer, that colonialism hasn’t gone away, it’s just changed its jacket, and that everything is a commodity.

The ice pick used to kill Trotsky resurfaced in 2005 when Ana Alicia Salas, daughter of a Mexican secret police officer offered it for sale. “I am looking for some financial benefit,” she told the Guardian back then, adding that “something as historically important at this should be worth something…” And it was, bought by a wealthy American collector named Keith Melton. Next year it and its bloodstains will go on display in Washington’s International Spy Museum.

And as Theresa May delivered her recent car-crash conference speech, eagle-eyed viewers noticed that she was wearing a bracelet featuring Trotsky’s sometime lover and fellow communist, artist Frida Kahlo.

Nobody knows why. After all, Trotsky himself argued that only a “United States of Europe” could provide the basis for peace and progress…