Distinguished scholar James D. Tracy shows how the Ottoman advance across Europe stalled in the western Balkans, where three great powers confronted one another in three adjoining provinces: Habsburg Croatia, Ottoman Bosnia, and Venetian Dalmatia. Until about 1580, Bosnia was a platform for Ottoman expansion, and Croatia steadily lost territory, while Venice focused on protecting the Dalmatian harbors vital for its trade with the Ottoman east. But as Habsburg-Austrian elites coalesced behind military reforms, they stabilized Croatia's frontier, while Bosnia shifted its attention to trade, and Habsburg raiders crossing Dalmatia heightened tensions with Venice.