Semiramis was believed to be the daughter of the goddess Derceto. She was exposed at birth (see also Oedipus, Maui and Feral Children; Snow White and Hansel and Gretel are examples from fairy tales of older children being exposed because of family rivalry or poverty), but she was attended by doves until found by shepherds and raised as their child.
When she grew up she married first Onnes and then Ninus, King of Assyria. When he died she ruled in her own right. She was also a famous general and is credited with building Babylon.