Bernardus Silvestris, also known as Bernard Silvestris and Bernard Silvester, was a medieval Platonist philosopher and poet of the 12th century. Bernardus' greatest work is the Cosmographia, a prosimetrum on the creation of the world, told from a 12th-century Platonist perspective. The poem influenced Chaucer and others with its pioneering use of allegory to discuss metaphysical and scientific questions. Bernardus also wrote the poem Mathematicus and probably the poem Experimentarius as well as some minor poems.