A Dictionary of Greek and Roman biography and mythology

Ὀρθία, Ὀρθίας, (or Ὀρθωσία) a surname of the Artemis who is also called Iphigeneia or Lygodesma, and must be regarded as the goddess of the moon. Her worship was probably brought to Sparta from Lemnos. It was at the altar of Artemis Orthia that Spartan boys had to undergo the diamastigosis (Schol. ad Pind. Ol. 3.54 ; Hdt. 4.87; Xenoph. de Rep. Lac. 2.10). She also had temples at Brauron, in the Cerameicus at Athens, in Elis, and on the coast of Byzantium. The ancients derived her surname from mount Orthosium or Orthium in Arcadia.

[L.S]