Turkey has an extensive military history with Alexander the Great, Achilles and the Ottoman Empire; just some of the many powers leading battles on Turkish soil.
In WWI Turkey sided with Germany and had to fend off Western Powers on multiple fronts – it was during this war that the Armenian Genocide took place, as well as many other atrocities against Christians and other minorities. The Ottomans had been losing power and diminishing in size over a couple of centuries, and in 1923 a modern Turkey was born, with Mustafa Kemal (better known as Ataturk) as President.
In the 1950’s they set about becoming a secular democracy but a variety of politically extreme parties, coupled with military interference have seen this littered with corruption and Kurdish separation. The single-party period ended in 1945, followed by transition to a multiparty democracy that has been plagued by military coups d’etat.
Turkey played a prominent role in the Gulf War and as the war ended millions of Iraqi Kurds fled to Turkey in fear of Saddam Hussein. The Kurds established the Kurdistan Workers Party (PKK) and began an insurgency against the Turkish government; the conflict continues today.
The current government, in power since 2002, has seen a marked improvement for Turkey economically and has successfully negotiated EU membership. Whilst secular, they are very pro-Islam and have made all education compulsory Islam-centred.
As for Turkish Christians, it is not illegal but neither is it legal to practise Christianity. Christians are very much in the minority and are typically not looked upon favourably by their Muslim counterparts.