sentences:  It has been speculated that Six Sky was the son of Siyaj Chan K'awiil II, a king of Tikal.Río Azul was first settled in the Middle Preclassic (c. 1000–350 BC) around 900 BC and underwent a period of notable expansion during the Late Preclassic, at which time a number of monumental temples were built.These have been dated to around 500 BC.