Chronomancy

Chronomancy is divination of the best time to do something, the determination of lucky and unlucky days, especially popular in ancient China.
The term "chronomancy", stemming from the Greek word "chronos" (meaning "time"), and the word "manteia" (meaning "divination") is also used in fiction to refer to a school of magic involving supernatural manipulation of time.
Time manipulation.
The best known historical figure that has been attributed the power of chronomancy is the Count of St. Germain, the eighteenth century philosopher, alchemist, and spiritualist. He has been believed to transcend time by reincarnation and eternal youth.
Role in modern fantasy.
In modern fantasy role-playing games, such as Dungeons and Dragons and other games set in the Forgotten Realms universe, chronomancy refers to a school of magic related to moving through and manipulating time.