Both Russia and Ukraine trace their cultural ancestry to the Kyivan Rus period in the early Middle Ages, when a loose federation of Slavic, Baltic and Finnic peoples formed a common identity. Missionaries from the Germanic peoples were eventually replaced by diplomats. This painting, depicting the Baptism of Prince Vladimir — or Volodymyr — in 987, hangs in Kyiv Cathedral.

Russia was under Mongolian rule in the late Middle Ages, but lively trade with the Hanseatic German cities continued. The period began with a victory over Teutonic knights in the so-called Battle on the Ice on a frozen lake in 1242. Sergei Eisenstein turned the battle into a patriotic Russian epic in the run-up to World War II.

Born in what is now Szczecin, then in Prussia, Catherine the Great acceded to the Russian throne in 1762, after the overthrow of her husband, also born in Germany. Her reign oversaw the Russian Enlightenment, whose intellectual ideals — freedom, liberty, and reason — she championed. Those ideals did not extend to Poland, however, which she partitioned with Prussia.

Like many of Europe's colonial monarchies, Prussia and Russia found common cause in opposing revolutionary France and the military campaign of Napoleon Bonaparte. The alliance was sealed at the Convention of Tauroggen in 1812 between a Prussian general and a German-born general of the Russian Imperial Army, in which many Prussian soldiers served.

In 1913, Kaiser Wilhelm II (right) invited his cousin Czar Nicholas II to Berlin for the wedding of his daughter. A year later, the two countries were at war, and four years later, both men had lost their thrones, with Nicholas executed in 1918. Millions of Russians and Germans were killed in the war, and both countries felt aggrieved by the terms imposed by the Western Allies.

Represented by foreign ministers Joachim von Ribbentrop (left) and Vyacheslav Molotov, Adolf Hitler and Joseph Stalin (right) signed a non-aggression pact in August 1939. The following month, both countries invaded Poland. Germany tore up the pact in 1941 with the invasion of the Soviet Union known as Operation Barbarossa. Nearly 14 million Russians and 6.8 million Ukrainians died during the war.

East Germany fell under the Soviet Union's influence after the war, an alliance that found its iconic image in the "socialist fraternal kiss" between German Democratic Republic leader Erich Honecker and Soviet leader Leonid Brezhnev in 1979. East Germans grew up learning Russian and until today many have more understanding and sympathy for the Russians and their President Putin than West Germans.

Chancellor Willy Brandt tried to normalize relations with the communist nations during his tenure from 1969 to 1974, a rapprochement that became known as "Ostpolitik." In 1970, Brandt (center left) signed the Moscow Treaty alongside Russian Premier Alexei Kosygin (center right), which formally recognized East Germany and temporarily abandoned the goal of German reunification in exchange for peace.

"Gorbi, Gorbi!" was the jubilant headline of Germany's mass-circulation Bild tabloid in June 1989 when Soviet leader Mikhail Gorbachev came to visit. For Germans he was — and still is — the hero who made the peaceful unification of the country possible.

German-Russian relations developed throughout the post-Soviet years, with German Chancellors Gerhard Schröder and Angela Merkel hoping that deepening trade ties would bind the countries together and soften Russia's authoritarian leader Vladimir Putin. Schröder initiated the Nord Stream pipeline project, which many believe left Germany dependent on Russian gas.

Artists dealt with possible implications of a war even before World War I broke out. When Emil Nolde painted ‘Soldiers’ in 1913, war was already in the air in Europe. The mood was divided: Apocalyptic sentiment and a fear of conflict had gripped some, but others were longing for the war to purge society of its ailments.

The painting 'Horrors of War’ by Ludwig Meidner can be seen as a prophetic image of the events that ensued. As early as 1911, his ‘Apocalyptic Landscapes’ showed a collapsing world that left people without protection.

With the beginning of the war, the colors seemed to disappear from Max Beckmann’s works. His ‘Declaration of War’ from 1914 is more a sketch than a painting. Beckmann developed a new language of expression that was characterized by simplicity and minimalism.

Paul Klee also dropped the traditional style. His ‘View of the Severely Threatened City of Pinz’ is from 1915. A year later, Klee was exempted from serving on the front lines and started working in a plane construction hangar near Munich. He spent his free time sketching and painting with quills and water color pens on both paper and cardboard.

In 1915, Raoul Dufy painted 'The End of the Great War’ as most of his fellow countrymen envisaged it. It was a glorified depiction of France’s victory, showing the German eagle at the feet of the Gallic rooster.

Belarusian-born artist Ossip Zadkine worked in a French army clinic on the Western Front, where he experienced the horror of battle first-hand. In 1916, he suffered from gas poison himself. He survived and translated his memories into images in a series of drawings.

German sculptor Wilhelm Lehmbruck created this sculpture of a naked man in 1915. He called it ‘The Fallen Man’. Like almost no other work in the exhibition ‘The Avant-Gardes at War’, it represents man’s vulnerability against the destructive forces of war.

Back in 1914, Russian artist Kazimir Malevich still created patriotic and folkloristic imagery. But his style changed radically from 1915 onwards. Malevich would become known as the originator of Suprematism, an art movement based on pure abstraction. His programmatic oeuvre ‘The Black Square’ is shown in the top center of this picture. It is a precursor of the post-1918 period.