John Wycliffe was so despised by the church because of his reform efforts that 20 years after his death in 1384, declared a heretic by a church council, his bones were exhumed, burned, and strewn in the river.
Wycliffe predates Martin Luther and the Reformation that was so effectual by about 150 years, but he addressed many of the same issues. He criticized church teaching that had no authority in the Bible. He denounced excessive practices that abused church authority, like selling indulgences for forgiveness and the Pope's demand for taxes. Most importantly, Wycliffe translated the New Testament into English, putting the Bible in people's hands rather than depending on the church for interpretation. The church tried to destroy copies of his translation, but copies survived.
His life's work laid the foundation for the ideas that took hold later in the Reformation that changed the church and the world.