The Twelve Virtues of a Good Teacher [Les Douze Vertus d’un bon Maître] by Brother Agathon, fifth Superior General of the Brothers of the Christian Schools from 1777 - 1795 is, in my view, after the monumental text we know as The Conduct of Schools, the most significant work in education in the Lasallian heritage. Some 100 years after the first schools, it affords a kind of benchmark by which to judge the fidelity of the Institute to the founding vision. This significance is primarily because of the inherent value of the text itself, but also because of its wide diffusion outside of the Institute. Translated from the original French into Italian in 1797 and into English, Spanish, Dutch, and German during the 19th century, the work was a major text in many Catholic Teaching Colleges until the 1930's.