Tzath I (Georgian: წათე), Tzathius or Tzathios (Greek: Τζάθιος) in Byzantine sources, was king of Lazica (western Georgia) from 521/522 to an unknown date.
[2] Upon his father's death, in 521 or 522, he refused to recognize the traditional suzerainty exercised by the Persian ruler over Lazica, rejected Zoroastrianism, and instead turned to the Byzantine Empire.
[3][5] Professor Cyril Toumanoff has conjectured that Tzath's reign lasted until circa 540, when he was succeeded by his possible son, Gubazes II.
Opsites, an uncle of Gubazes, is mentioned by the 6th-century Byzantine historian Procopius as "king of the Lazi" on one occasion and as prince of east Abasgia on the other.
Toumanoff, however, further assumes that Opsites was a member of the Lazic royal family and prince of Abasgia, but never a king of Lazica, thus making Gubazes a direct successor of Tzath I.