When did the first Latin texts describing Japan emerge? When, how and why did some Japanese people began to actively communicate in the Latin language as early as the 1580s? How did Latin, the language of the ancient Romans and a hallmark of the West (the 'European sign'), change through contact with a region and culture so remote from its home? This monograph addresses these and other questions while looking at European-authored travelogues, missionary reports, plays, a Vergilian epic and even haiku as well as Japanese-authored Latin prose and verse. Transcriptions of several never-before published Latin texts composed by the Japanese from the 1610s to 2024s are appended.