This essay extends the retrieval of the Franciscan intellectual tradition into the sciences by presenting the vocation and work of three Franciscan scientists. Friar Bartholomew the Englishman taught his fellow Franciscans with the best available scientific knowledge to prepare them for preaching in foreign lands. Friar Roger Bacon conducted research into the natural world to advance scientific knowledge in service of the Church. Friar Bernardino de Sahagún investigated the life, worldview and culture of the Aztec peoples in New Spain (now Mexico) to interpret these for his fellow Franciscans. In the Franciscan tradition, learning about nature helps one grow in wisdom, and thus Franciscan science is knowledge for love. This essay argues that the retrieval of our Franciscan intellectual tradition could and should include the sciences.