Francisco Xavier Baptista (?-1797) is one of the most important composers in the field of the Portuguese repertoire for keyboard instruments of the second half of the eighteenth century. His collection of twelve sonatas for harpsichord published in Lisbon around 1770 features amongst the rare works for keyboard instruments which were printed in Portugal in the course of that century. Despite the importance of his work and the relevance of his professional activity as organist of the Basilica de Santa Maria in Lisbon, the biographical details about Francisco Xavier Baptista that are currently available continue to be scarce. The recently released data about the professional career of this musician and composer, specifically related to the occupation of the post of organist at the Basilica of Santa Maria and the accomplishment of musical activities outside the institution, treat Francisco Xavier Baptista and Francisco Xavier Baxixa as a single person. However, previous informations indicates Francisco Xavier Baptista and Francisco Xavier Baxixa as two distinct musicians who lived at the same time.