Complex sentence: The Yongle Emperor sought to legitimize his reign by imposing the foreign countries to recognize their tributary status within Ming China's greater world order, which came to entail a diplomatic relationship based on a visible presence of a militaristic naval force in foreign waters.
Split into simpler sentences: The Yongle Emperor legitimized his reign by imposing the foreign countries to recognize their tributary status in the greater Ming world order. This would entail a diplomatic relationship based on a visible presence of a militaristic naval force into the foreign waters.