Shiniki no Mahoutsukai: Kami ni Aisareta Rakudaisei wa Mahou Gakuin e Kayou

A wizard from the Divine Realm who has mastered magic and proposed a new magical theory. Just before his death, he uses reincarnation magic and is reincarnated 500 years into the future! He starts a new life as a farm boy named Lucien, but he finds himself in a world where the common sense of his previous life no longer applies and magical technology has declined...!?

(Source: Mag Comi, translated)