In late 1785, four ambassadors left India on a ship bound for the Ottoman Empire. They brought with them a retinue of 400, who sailed to Muscat and Basra, and four elephants, who did not make it that far. Such grand diplomatic missions across the Indian Ocean were not unheard of, but this one was particularly remarkable because it was sent not by the long-lived Mughal empire, but by Tipu Sultan of Mysore, who was then in between wars against the British. Both Ottoman and Indian historians have touched on this mission, but they have tended to talk past each other. This paper, drawing on Ottoman and British archives, Ottoman and Indian chronicles, and travel narratives, begins an effort to think through the mission’s implications, arguing that it had a major but overlooked effect on Ottoman military reform and modernity. The mission failed in its remarkable main goal of building a transoceanic anti-British alliance, to be cemented by exchanging Basra for an Indian port of the Ottomans’ choice. Many of its members died of disease in Istanbul. But during its residence in the Ottoman capital, this mission attracted tremendous attention. It included 200 sepoys, long-service volunteer soldiers trained in the new European drill. They performed their exercises before rapt and excited audiences of Ottoman officials, who were then preparing for war their Eurasian rival, Russia, with its disciplined conscript armies. Grand Vizier Koca Yusuf almost immediately acted to follow the Indian example. By carefully following both the subsequent activities of Ottoman officials and the memory of chroniclers, I show how he and other Ottoman elites received, translated, and modified that example. Even as they copied the idea of trained, Muslim soldiers fighting in formation, the Porte innovatively drew upon very different sources of available labor, relying on involuntary recruits from across Eurasia—Russian prisoners, Austrian deserters, and eventually Ottoman Muslim conscripts. The resulting Nizam-? Cedid army is often seen as a straightforward imitation of western European military innovations. But Ottoman military reforms must instead be seen in two different contexts: that of diplomatic and cultural exchanges across the Indian Ocean, and that of military conflict and military labor in Eurasia. The Ottoman Empire was part of both contexts, and brokered between them. But at the same time, the paper will raise questions about what we gain and lose by moving between the historiographical frames of “Eurasia” and “the Indian Ocean.”