Tada no Murabito no Boku ga, Sanbyakunen-mae no Boukun Ouji ni Tensei Shite Shimaimashita: Zense no Chishiki de Ansatsu Flag o Kaihi Shite, Odayaka ni Ikinokorimasu!

Prince Rudolf gained knowledge of the future 300 years from now during a near-death experience. He uses his wits to change the future in which he will be assassinated as a tyrant prince.
Meanwhile, discrepancies between the story passed down to posterity and reality gradually emerge...