Temporal Defense Initiative (TDI) was an organization that was created in the 28th century. It was established in the year 2769 following the signing of the Temporal Accords by the various galactic powers. The body was composed of Temporal Operatives from the various signatories and consisted of agents from various historical periods. The goal of the organization was the protection of the timeline from those that sought to alter history. (STO video game: Agents of Yesterday)