How do you mean? In classical times, the Western parts of what we today call Turkey were part of the Greco-Roman sphere of influence and you can still see remains of many well-known sites like Ephesus. Western Turkey remained in the "Western" or "Christian" sphere of influence into the early middle ages. There are plenty of early Christian sites and a great part of the career of the apostle Paul was spent in Western Turkey. Starting probably around 1100 Turkic speaking peoples started to move west and gradually took over Turkey from the Byzantines, culminating famously in 1453 with the fall of Constantinople to the Ottomans. The Ottoman Empire remained its own separate polity and was considered more or less part of the Eurosphere, albeit a Muslim rather than Christian one, up until after WWI when it, like many other European countries, underwent a revolution that turned it from a monarchy into a republic. At times, the Ottomans were allied with nations like Germany and Austro-Hungary, but it has never been ruled or colonized by other Europeans.

Do you mean the country of Turkey? The Ottoman empire? The landmass of turkey, The Anatolian Peninsula? Your question is very unclear should've taken the time to explain