The Time Stone was one of the six Infinity Stones, the remnant of a singularity that predated the universe, representing the element of time, giving the wearer of the Eye of Agamotto the power to control time. It was contained inside the Eye of Agamotto and placed under the protection of the Masters of the Mystic Arts. Doctor Strange took possession of the Stone and used it to defeat Dormammu, after that Strange kept the stone and protected it.