Jerome was a lawyer, priest, hermit and scholar responsible for the revised latin translation of the bible - a labour of 30 years the vulgate bible is still in use. Of him, St. Augustine apparently said "What Jerome is ignorant of, no man has ever known." He spent many years as a hermit in the Syrian Desert where legend has it, he removed a thorn from a Lion's paw and the lion remained by his side afterwards.
St. Jerome is the patron of Libraries - among other areas and perhaps his lion is the patron of the stone lions on Public library steps, not to mention the many library cats. He is also the patron of archeologists, archivists, Bible scholars, librarians, schoolchildren, students and translators.