Question: "What previously acted as a buffer for the Ottomans?" Context: "For over 200 years, Russia had been expanding southwards across the sparsely populated "Wild Fields" toward the warm water ports of the Black Sea that did not freeze over like the handful of other ports available in the north. The goal was to promote year-round trade and a year-round navy.:11 Pursuit of this goal brought the emerging Russian state into conflict with the Ukrainian Cossacks and then with the Tatars of the Crimean Khanate and Circassians. When Russia conquered these groups and gained possession of southern Ukraine, known as New Russia during Russian imperial times, the Ottoman Empire lost its buffer zone against Russian expansion, and Russia and the Ottoman Empire fell into direct conflict. The conflict with the Ottoman Empire also presented a religious issue of importance, as Russia saw itself as the protector of Orthodox Christians, many of whom lived under Ottoman control and were treated as second-class citizens.(ch 1)" Answer:
The answer to this question is:
southern Ukraine