Religion had always been important in Imperial Russia. As early as the seventeenth century, Russian expansion, even the Russian empire itself were perceived by Russian statesmen and historians as the Orthodox Crusade (as opposed to the famous series of Crusades in the middle ages).
The rapid dizzying expansion of the Russian empire encouraged the Russians to proclaim Moscow (their own Holy city) as the Third Rome (after Rome & Constantinople). Incorporation of the Orthodox Christian faith into the Russian identity was State and Church sponsored.
Religious fervor and zeal for protecting the Holy lands and Christian pilgrims from Muslim aggression were a significant factor in vitalizing the Christian kingdoms into building armies and sending campaigns to the Middle East. The same tactics were sought once again in Imperial Russia. This time, not just for restoring the Holy lands into the Christian fold, but to resurrect the Byzantine Empire as well.
The Russians missed the first series of crusades in the Holy Lands (1095 – 1291); the Kievan Rus’ started embracing Christianity, in the Byzantine Orthodox faith, in the 11th century A.D. So, the Russians embarked on their own crusade, starting the early 18th century.
The early Russo-Turkish skirmishes and wars were a combination of direct confrontations and proxy wars. In Ukraine and around the Black Sea, the Tatar Khanate of Crimea (1441 – 1783) did the Ottoman Sultan’s bidding for a long time. However, with the increasingly powerful and brutal Russian intervention, the Ottoman entered the fray of a long series of wars… and lost spectacularly. The first devastating blow to the Ottoman prestige came with the 1768-1774 war. A war vital in two aspects: it proved to weary Europe that the Russian Empire was indeed the behemoth they feared it was, and the Ottomans were no longer so.