The key factor in the rise of the Ottoman Empire in Europe was its strategic location at the crossroads of Europe and Asia, facilitating trade and military expansion. The Ottomans capitalized on the declining Byzantine Empire and internal conflicts among European states, enabling them to conquer substantial territories. Additionally, their military innovations, including the effective use of artillery and disciplined infantry (the Janissaries), played a crucial role. The empire's tolerance of diverse cultures and religions also fostered loyalty among conquered peoples, allowing it to maintain stability and expand its influence throughout the region for centuries.