A bard is a poet who specializes in passionate, lyrical, or epic verse. Bards were originally Celtic eulogy and satire composers; the name grew to indicate a tribal poet-singer skilled in writing and performing poems about heroes and their exploits. In an age when most people could not read, these poets were important educators and role models. They also made music for ceremonial occasions such as royal weddings. Bards are sometimes described as "minstrels" because they would travel from court to court with their poetry performances and musical instruments. However, while minstrels may have been involved in the creation of some songs, there is no evidence that they were full-time musicians before the 13th century. Bardic poetry seems to have evolved independently from medieval troubadour song, although both probably had similarities with the sacred poetry of other cultures (such as the Hebrew prophets). In ancient Greece, a bard was called a tragōdus. Like their Celtic counterparts, Greek tragōdies traveled around taking part in religious ceremonies and games and composing poems and songs about famous athletes and warriors. Unlike their Celtic predecessors, however, Greek tragōdies were not only poets but also actors, mimes, and storytellers. They used theater techniques such as masks and costumes to add effect to their performances.