Many different factors combine to define the transition from the late medieval to Renaissance period. One of the major ones is the rediscovery of a wide range of ancient materials in the wake of the fall of the Byzantine Empire. In terms of language, there was a simultaneous shift from the medieval church Latin to Ciceronian Latin in the wake or recovery of Cicero's letters, along with a striking rise in vernacular literary. The Reformation (and counter-Reformation) marked a shift in religious thinking, and especially a diminution of Church authority and emphasis on direct reading of primary texts using early manuscripts. Philosophy became more practical and secular, with increasing focus on the natural world.