A number of historians have come to the conclusion that Geoffrey Chaucer, author of The Canterbury Tales, was murdered.
The motive: Geoffrey had been a friend and policy advisor to King Richard II. When Henry IV took the throne by force (Richard II was imprisoned and died shortly thereafter), the new king would have naturally been somewhat suspicious of Chaucer. Could Henry IV really trust Chaucer, when Chaucer's friend had died as a direct result of the power grab by Henry IV?
There is circumstantial evidence: Chaucer spent his last days in Westminster Abbey, where the church could offer him immunity from prosecution (this is the historical concept of "sanctuary"). When Chaucer did mysteriously die, he was not given the impressive funeral one would expect for someone with literary, political, and social connections.