Inachus
Ἴναχος
The river god who read the name his daughter, turned into a cow, traced in the sand with her hoof.
He is counted as the first river and first king of Argos.
When his daughter Io was changed into a cow and vanished, the river sank into grief.
Ovid writes that Io, in cow form, revealed herself by writing her own name in the sand with her hoof beside her father's stream. It is the saddest written conversation in myth.
SourcesOvid, Metamorphoses