Painting history: Manet on a mission Up until Maximilian's demise, Manet had actively avoided historical subject matter. How, then, to explain the three paintings of one event? In part, it was out of the indignation that this republican artist felt towards his emperor's colonial machinations. Others argue Manet felt some kind of kindred spirit towards Maximilian, both having been born in the same year (1832) and both having been naval cadets in adolescence. Just as important, though, was the impact of Spanish painting. French artists had long been trained in the disciplined, linear, Italianate tradition, yet the manière espagnole - all stark and sudden - was now growing increasingly popular. Manet's appetite for it early in his career was boundless, and Goya's El Tres de Mayo - which he saw in the Prado during his sole trip to Madrid, in 1865 - is a clear model for his Maximilian paintings soon afterwards. Goya's image is of Spanish freedom fighters being executed by Napoleon I's invading forces, and Manet is fully alive to the bellicose, Bonapartist link between that work and his own. He dresses the Mexican firing squad in French military uniforms - as if to suggest it was the French who, ultimately, were Maximilian's killers. What's more, the sergeant on the right, glancing away indifferently while the shots are fired, looks considerably like Napoleon III. Because of its missing parts - most obviously, the absent Maximilian - the National's Execution is often deemed the least important of Manet's three efforts. Certainly, the first painting (now kept in Boston) is a sketchy, murky, expressionistic success - Manet's instant response to news of the execution - while the third painting, from 1869, (now kept in Mannheim) is the most carefully finished and composed. The London canvas, though, still has much to recommend it. Maximilian was shot alongside his two Mexican ally-generals, Mejía and Miramón, and the former - in a show of dignity and loyalty - movingly clasps his hand in their final moment. The empty landscape behind them, meanwhile, suggests the action isn't restricted to Mexico but could be anywhere, at any time. Manet is asking the same questions we are in the 21st century about the risks and responsibilities of foreign invasion. Napoleon III himself only heard news of Maximilian's death two weeks after it happened, and his government ensured the public was merely drip-fed select information about it thereafter. News travels infinitely faster now, of course - but in our age of Redaction, the official cover-up seems painfully modern. In its way, the fragmentary fate of Manet's canvas - matching his source material - seems really rather apt. "The Execution of Maximilian" tours the UK throughout 2014, starting at Canterbury's Beaney House of Art & Knowledge, from Jan 17 to Mar 16; nationalgallery.org.uk/whats-on