Starting from the premise that all empire building involves ideological constructs justifying the violence that accompanies such efforts, this article concentrates on elucidating the case of the Portuguese in Asia, specifically in Japan. Although well beyond the formal Portuguese thalassocracy in Asia, the Japanese islands were exposed for about a century, between 1543 and 1640, to the informal presence of Portuguese traders and missionaries. The symbiotic relationship between these two groups was based on the experience that, in Japan, the trade was difficult to conduct, for violence was always lurking beneath the surface of the trading relationship. We know of several instances when such violence actually exploded into major armed clashes, and many other times violence was narrowly averted through the mediation of the missionaries.Based on original research in the archives of Portugal and Spain, this article analyzes the records that the leaders of the Portuguese who came to Japan in the sixteenth century, the so-called capitães mores, have left behind. Finding that a significant number of these men were or later became members of the Order of Christ or were closely related to such members, it then explores their mindset through a survey of the function of this military order in Portuguese society of the late Middle Ages. The result is a group portrait of thirty-seven men who may be considered a representative sample of the Portuguese leading both the formal and informal empires in Asia. This portrait will clarify why both Japanese and Portuguese authorities agreed, at least during the second half of the sixteenth century, that the Jesuit missionaries were an indispensable presence in Japan. [ABSTRACT FROM PUBLISHER]