Who actually provoked who? Maybe Russia was testing Turkey's "red line"? (see image below for more on this). Russia could argue that it violated sovereignty for 20 seconds while NATO does it every day in Syria.
They way I see it, Turkey and Russia are both somewhat nasty, semi-dictatorships. And both have a lot of nationalist people in them that hate the other country. Recall, Turkey was a stalwart in the Cold War (2nd largest military in NATO in those years) -- a key ally against the Soviets. The bad blood actually goes back centuries as the Ottomans and Russians fought multiple battles - all the way back to Peter the Great and beyond -- a "Clash of Civilizations" (and geography).
Anyways, we know pretty much what Russia wants out of this current mess.
But what about Turkey? They are more complex. Here is what I think --
Originally, back in March 2011, they did not pick a side. But when Assad lied directly to Turkey's FM about murdering protestors, Turkey decided Assad needed to go. Then, in June 2012, Assad shot down a Turkish jet.
Erdogan then opened the border to anyone who wanted to fight Assad and began laying plans to support a Muslim Brotherhood-style post-Assad government in Syria. This was despite the fact that, in the early going, the FSA was dominant. But Turkey's logistical support (and Qatar's money) instead went to Brotherhood-sympathetic rebel units. These included the extreme Syrian groups -- Ahrar al-Sham and al-Nusra. Without that support, both these groups would have been completely wiped out by now. On top of all of this, there is some evidence that Turkey has even supported ISIS. Keep in mind they are a NATO member so this would be pretty wild if true. Russia claims it has happened.
In March 2013, Erdogan reached a cease-fire with the Kurds (which lasted until the Fall of 2014). It was during this period, with the border with the Kurds peaceful, that Salafiist jihadis really began to pour into Turkey from around the globe. This loose border played one of the biggest roles in the growth of ISIS. Besides all the people (most of whom were funneled through the Balkans), there was the money, weapons, oil and antiquities. The Turks could have shut this down along time ago which would have seriously curtailed the growth of ISIS, but they didnt.
And now, only recently, Turkey finally took a position against ISIS, and began to use its own military. Of course, while they bombed some ISIS targets, they also bombed the Kurds in Iraq. This is also when they finally allowed the US to use Incirlik as a base to bomb ISIS.
So Turkey is now in an odd position. They still want Assad out but now they are getting threatened by ISIS who says it will create chaos inside Turkey if they shut the border. There has already been a suicide bombing in Istanbull in 2015 (Turkey relies heavily upon tourism). Plus there is the reverse refugee flow which has tilted ethnic balances.
On top of all this, remember Turkey's biggest fear has always been is the creation of a independent Kurdish state out of some part of Syria. From which the Kurds will launch even more terror strikes against Turkey. Turkey definitely fears this more than they do ISIS.
So, here is my guess -- Turkey still wants Assad gone. And they think he should go first, then ISIS. In addition, they are not at all happy with the lack of support they got from NATO states (especially after Syria shot down their fighter jet). So they feel they are somewhat on their own. Lastly, I think the reason that they finally declared against ISIS is because they want to have a large voice in who replaces them. They wont let it be the Kurds.
Here are some details of what Turkey says it told Russia --
Last edited: Nov 24, 2015