Tada no Murabito no Boku ga, Sanbyakunenmae no Boukun Ouji ni Tensei shite Shimaimashita: Zensei no Chishiki de Ansatsu Flag wo Kaihi shite, Odayaka ni Ikinokorimasu!

During a near-death experience, Prince Rudolph obtains knowledge of the future 300 years from now. He uses his shrewdness to change a future in which he is assassinated as a tyrannical prince! But in doing so, discrepancies gradually creep into the stories that will be handed down to future generations...

(Source: Bushiroad, translated)