More often than not they have been bitter geopolitical foes rather than friends. The fledgling - and now increasingly fragile - alliance that Russia's Vladimir Putin and Turkey's Recep Tayyip Erdoğan have been building, irking in the process Ankara's NATO allies, has been rubbing against the grain of the history, say analysts.
If the two countries end up fighting each other over the fate of northern Syria, it would in fact be a return to their traditional historical enmity - one which has seen them wage war against each other in every century since the 16th. The first erupted in 1569 when the Ottoman army besieged the Volga delta town of Astrakhan, but was forced to retreat by the Russia's Ivan the Terrible.
In all but one of a subsequent series of wars, which were fought over access to the Black Sea, the ownership of the steppe lands of Ukraine and control of the Balkans, has Turkey come off worse, losing territory and influence as a consequence. The clashes in the 19th century shrunk the Ottoman Empire, dubbed the "sick man of Europe," hastening its collapse, say historians.
History says odds against Turkey
Only in the Crimean War of 1854 to 1856 did the Turks triumph - and that was in large part thanks to the support they received from France and a reluctant Britain. "I despise the Turks for I consider their government the most evil and most oppressive in all the World," George Hamilton-Gordon, the 4th earl of Aberdeen, and Britain's prime minister, told friends during the war.
Russian Czars, including Peter the Great and Catherine the Great, eagerly took advantage of Ottoman decline to encourage Balkan and Slav nationalism and to expand Russian territory in Central Europe and the Caucuses. In the war of 1768-1774, another conflict that saw Russian arms largely victorious against the Ottomans, Moscow grabbed part of Moldavia and Crimea as well as the Pontic-Caspian steppe, a vast swathe of land stretching from the northern shores of the Black Sea as far east as the Caspian Sea.
And Russia emerged from the war as one of Europe's primary military powers.
But if the history of defeats should make Ankara highly wary in its standoff in northwestern Syria with the nuclear-armed Moscow and its client Syrian President Bashar al-Assad, Western powers should also worry about what the possible wider and longer-term ramifications could be of a 21st-century Russo-Turkish military clash.
The Crimean War, made infamous by the hubristic Charge of the Light Brigade and other dreadful military blunders and blessed by the nursing of Florence Nightingale, "set in train the succession of European wars and power-struggles which dominated the second half of the nineteenth century," writes the British military historian Trevor Royle in his book "Crimea."
Those conflicts "paved the way for the greater conflagration of 1914," the first of the 20th century's shattering worldwide conflicts, he adds. As with the Crimean War, so, too, one now between Moscow and Ankara would likely threaten the stability of Europe. Analysts say a war between Russia and Turkey could place NATO in a difficult and possibly terminal dilemma.
The Article Five dilemma
Ankara, they say, would likely invoke the principle of collective defense enshrined in Article Five of NATO's founding treaty. The article says the alliance sees an attack on one member as an attack on all and is the very bedrock of the alliance and reason for the alliance's existence.
Doubts have already been cast in recent years by NATO members about their commitment to Article Five, leaving a cloud of ambiguity hanging over the principle of the bloc's collective defense pledge. U.S. President Donald Trump has at times questioned whether he would be prepared to respond to an Article Five appeal, notably at a NATO summit in 2017 during which he refrained from explicitly endorsing the principle of mutual aid.
Two weeks later, Mr. Trump reversed course, saying in impromptu remarks that the U.S. would indeed come to the defense of a NATO ally. But in an interview with Fox News anchor Tucker Carlson in 2018 the U.S. leader equivocated again on whether Washington would come to a NATO ally's defense, if attacked, citing as an example the Balkan country of Montenegro, which has recently joined the military alliance, and worrying aloud that Montenegro might unleash a third world war.
Not just Trump
But President Trump isn't the only Western leader to question Article Five, which has only been invoked once, in 2001 after the September 11 terror attacks. In November, France's Emmanuel Macron sounded less than enthusiastic about the collective-defense pledge. When asked in an interview with Britain's The Economist magazine whether he believed in the effectiveness of Article Five, he replied: "I don't know," adding, but what will Article Five mean tomorrow?"
In a poll conducted this month by the Pew Research Center, many in alliance member countries expressed reservations about fulfilling collective-defense obligations. The Center reported that despite NATO's largely favorable ratings among member states, there is widespread skepticism about Article Five. When asked if their country should defend a fellow NATO ally against a potential Russian attack, a median of 50% across 16 NATO member states say their country should not, compared with 38% who said their country should abide by Article Five.
Ankara would likely threaten to open the refugee floodgates once again, if NATO failed to leap to Turkey's defense, say analysts, risking further intolerable strain on EU solidarity. But there is little enthusiasm for Erdoğan among Europe's leaders, who have chafed at Turkey's slide towards authoritarian rule and bristled at the Turkish leader's playing habit of playing Europe off against Russia and vice versa in his efforts to get what he wants.
The rising tensions between Moscow and Ankara is not a surprise to Jonathan Schanzer, analyst at the Foundation for the Defense of Democracies, a Washington-based think tank. Last month, in an interview with VOA, he predicted that the Russian-Turkish relationship is weighted with geopolitical conflicts that risked undermining it.
"The Turks have been gravitating to the Russians, even as their vision of Syria directly conflicts with that of Putin," he said. He forewarned that the fledgling partnership risked collapse because of the grandness of the geopolitical ambitions of the two key players, Putin and Erdoğan, with one wanting to revive Russia as a superpower, and the other envisaging restoration of Ottoman greatness.