In 1976, however, the IAU resolved that the theoretical basis for ephemeris time was wholly non-relativistic, and therefore, beginning in 1984 ephemeris time would be replaced by two further time scales with allowance for relativistic corrections.
The International Astronomical Union (IAU) decided in 1976 that the theoretical foundation of ephemeris time was not relativistic, so starting in 1984, it was replaced by two new time scales that accounted for relativistic effects.