The use of colour to add meaning to images is longstanding practice, and can be traced back to ancient Egyptians, who tended to use it to distinguish males from females. Most probably the result of their belief system, females were often depicted with paler or even white skin, while men were more swarthy in appearance.

In this fresco of a funeral procession from the tomb of Ramose, dating from about 1353–1336 BCE, there’s a clear distinction in skin colour between the central group of women, and the men on the left and right.

This passed through into the Renaissance.

This can be most apparent in paintings of Adam and Eve, here that made by Maerten van Heemskerck in about 1550, where Eve is as white as ivory.

Annibale Carracci’s Latona and the Lycian Peasants, probably from 1590-1620, shows the near-white goddess Latona placing her curse on the swarthy-skinned locals.

After the Renaissance, this colour-coding largely disappeared, only to return at the end of the nineteenth century.

Evelyn De Morgan’s Boreas and Orithyia from about 1896 shows the darker Boreas, the north wind, bearing the paler Athenian princess Orithyia aloft.

In the early twentieth century, the former Nabi artist Félix Edouard Vallotton painted a series of narrative works, including his Perseus Killing the Dragon, from 1910, a thoroughly contemporary interpretation with a marked contrast in skin colour. This is most evident where their feet are close together at the lower edge of the painting.

Independent of that coding, paintings of hell and devils developed their own colour schemes.

This detail from Giotto’s fresco of The Last Judgment in the Scrovegni Chapel in Padua, Italy, was painted in 1306. It follows the early convention that its humanoid demons are colour-coded blue, with some in brown, in contrast to its densely-packed and near-white victims seen undergoing punishment. There’s no colour-based distinction between men and women here, though.

Luca Signorelli’s large fresco in the San Brizio Chapel in Orvieto shows the seething mass of The Damned (1499-1502). His colour-coding is richer, and there’s precious little sign of flames, fire, or even rocks, just a dense mass of people being tormented.

Bonifazio Veronese’s St Michael Vanquishing the Devil from 1530 shows a dark-skinned humanoid with draconian wings, which may have descended from older images in which the Devil (with the definite article) is shown as a straight dragon. This artist isn’t the great Paolo Veronese, but a Venetian painter whose work influenced Tintoretto.

This visual distinction extends to more recent paintings, including Henry Fuseli’s The Nightmare from 1781. The daemonic incubus seen squatting on the torso of a young woman is swarthy in colour compared to his victim’s pallor.

Ary Scheffer used clear colour coding in his Temptation of Christ, from 1854, where the fallen angel is trying to get Christ to jump from a pinnacle so that he could rely on angels to break his fall.

Most recently, some have tried to interpret this as racialism, but these codings have older origins, and only appear in skin colour, not overall appearance. It would be nonsense to suggest that any of these devils were intended to represent North Africans, for instance.

Neither Napoleon nor his wife Joséphine were faithful during their marriage, but she failed to produce the heir that the Emperor wanted. In 1809, he informed her that he had to find a wife who could provide an heir, and they divorced the following January. Pierre-Paul Prud’hon went on to paint her successor Marie-Louise of Austria as well.

Following his marriage to the eighteen year-old Marie-Louise of Austria, the new Empress became pregnant, and on 20 March 1811 gave birth to their son, who was soon made King of Rome. That year, Prud’hon painted this Portrait of the King of Rome, setting him asleep in a glade with a waterfall behind. Prud’hon was also involved in decorating a crib for the infant.

Meanwhile, the Emperor’s youngest sister Caroline had married one of Napoleon’s most brilliant cavalry officers who succeeded Joseph Bonaparte (the emperor’s older brother) as King of Naples. Élisabeth Louise Vigée Le Brun, known best for her brilliant pastel paintings, used oils for this portrait of Caroline Murat, Queen of Naples, with her Daughter Letizia in 1807.

Napoleon had continued leading French forces from his success at the Battle of Austerlitz in Austria in 1805, through Eastern Europe, then in Spain in 1808, where he installed his older brother Joseph as king. However, the French invasion of Russia in the summer of 1812 proved a disaster.

Ary Scheffer’s account of The Retreat of Napoleon’s Army from Russia in 1812 (1826) shows this march of death starting from Moscow in the middle of October 1812, which took until the middle of December to clear Russian territory. In the appalling winter weather, Napoleon’s Grande Armée is claimed to have shrunk from 100,000 to around 22,000.

The tide had turned. The following year Napoleon was decisively defeated at Leipzig, France was invaded, he was forced to abdicate in April 1814, and was exiled to the island of Elba, in the Mediterranean between Corsica and Tuscany. He escaped and returned to France, where he and his forces were defeated at the Battle of Waterloo in 1815. He was finally sent to the island of Saint Helena in the South Atlantic, where he died in 1821.

JMW Turner’s War. The Exile and the Rock Limpet from 1842 shows an imagined moment from Napoleon’s exile on the British island of Saint Helena, no doubt inspired by the return of the emperor’s ashes for state burial in France in 1840. In the background is one of the British sentries stationed on this remote island to guard the former emperor. Napoleon is bowing slightly to a tiny limpet on a rock, a symbol of the futility of war. The sunset behind forms the sea of blood resulting from Napoleon’s many battles across Europe.

Michel Ney (1769-1815) was a leading military commander during the French Revolutionary and Napoleonic Wars, and was made a Marshal of France by Napoleon. Following Napoleon’s defeat and exile in the summer of 1815, Ney was arrested, and tried for treason by the Chamber of Peers. He was found guilty, and executed by firing squad near the Luxembourg Gardens in Paris on 7 December 1815. He refused a blindfold, and was allowed to give the command to fire upon himself.

Jean-Léon Gérôme’s Death of Marshal Ney (1868) uses a similar narrative approach to Gérôme’s earlier paintings of the murder of Caesar, in showing a moment after the climax of the story. Ney’s body is abandoned, slumped and lifeless on the muddy ground, his top hat apart at the right edge of the canvas. Behind where he stood but a few moments ago there are half a dozen bullet impact marks on the wall, as the firing squad is being marched off, to the left and into the distance.

For a few brief weeks after Napoleon’s abdication, he tried to make his son the King of Rome his successor, as Napoleon II.

His cousin Louis Napoleon Bonaparte had been born in the Tuileries Palace in Paris. After Napoleon I had been sent to Saint Helena, the rest of the emperor’s family were dispersed elsewhere. Louis Napoleon joined the Swiss Army, developed political aspirations, and in 1836 led an attempted coup from Strasbourg. After a period of exile in London, he attempted a second coup in 1840 that quickly turned into a fiasco. He escaped from prison in 1846, fled to London, only to return to Paris after the French Revolution of 1848. He then gained a place in the National Assembly, where he campaigned successfully for election as President of France. He staged a further coup in December 1851, and won a referendum enabling him to proclaim himself Napoleon III, Emperor of the French, on 2 December 1852.

Gérôme articulated Napoleon III’s aspirations for empire in his elaborate and formal painting of the Reception of Siamese Ambassadors by Napoleon III (1864), depicting a grand reception held at Fontainebleau on 27 June 1861. Gérôme had attended in the role of semi-official court painter (commissioned by the State), made sketches of some of the key figures, and was further aided by photographs made by Nadar. He also included himself, and the older artist Ernest Meissonier (1815-1891), in the painting: I believe that they are both at the back, at the far left.

Cabanel’s life-sized full-length portrait of the Emperor Napoleon III from about 1865 proved controversial, as many felt that his image of their emperor should have greater grandeur. Some critics even accused Cabanel of making him look like a hotel manager or waiter, and I can see their point. The Empress Eugénie and Napoleon’s family had no such qualms, though: Cabanel’s painting was hung in the Tuileries Palace, and when the Second Empire collapsed, and the empress fled to Britain, she took this painting with her into exile.

Napoleon III clearly lacked his uncle’s flair for military leadership, and declaration of war against Prussia on 19 July 1870 led to a series of disastrous defeats ending with the Battle of Sedan, a fortified French city in the Ardennes. The French Army surrendered to the Prussians and Napoleon III became a prisoner of war.

Emil Hünten’s undated Welcome of Empress Eugénie by Prussian Soldiers shows an event that never occurred. When the Empress was told of her husband’s surrender to the Prussians at the Battle of Sedan, she is reported to have said: “No! An Emperor does not capitulate! He is dead!… They are trying to hide it from me. Why didn’t he kill himself! Doesn’t he know he has dishonored himself?!” With hostile crowds forming outside her Tuileries Palace, she slipped out to find sanctuary in the company of her American dentist, then fled to England by yacht on 7 September 1870. She was later joined by the former emperor, and the couple lived at Chislehurst in Kent.

Perhaps the most lasting memorial to these French emperors is the Suez Canal. During Napoleon’s Egyptian campaign in 1798, he had engineers and others search for an ancient canal running north from the Red Sea. In 1804, the new Emperor considered constructing a canal to connect the south-eastern Mediterranean with the Red Sea. Early in the reign of Napoleon III, Ferdinand de Lesseps obtained a concession to construct the canal that Napoleon I had dreamed of. The Suez Canal was officially opened on 17 November 1869, with both the Empress Eugénie of France and the Crown Prince of Prussia present as guests.

Painted by the great marine artist Ivan Aivazovsky shortly after that official opening in 1869, Suez Canal shows a convoy of ships passing through in an unearthly light. Within a year the Second Empire had fallen, but Napoleon’s canal went on.