There is still discussion about the meaning of her name, but it may have been "throne" or "seat", see also the throne that is often depicted on her head. In any case her links to the throne are also illustrated by the many representations of Isis with the child Horus on her lap, breast feeding him who would later become king. Every living king of Egypt was the personification of Horus.
Well known is her role as the wife of Osiris. She searched for his body after he was murdered, and assembled the pieces of it into the first mummy. After this she reanimated Osiris, using her wings to give him the breath of life; then Horus was conceived. After his birth Isis hid him in the Delta marshes near Chemmis, to protect him against Seth. However, other dangers were lurking, like scorpions, crocodiles and snakes, and Isis had to protect Horus against these as well. In some cases she seems to have been unsuccessful, because there are texts on so-called magical stelae which tell us that the child was stung after all, and that Isis needed her magical powers to cure him.
Isis was associated with many other goddesses, above all with Hathor; the name of the latter means "House of Horus", possibly indicating that she was the original mother of Horus. She gave the cow horns and sun disk, often depicted in her head, to Isis. Through Hathor Isis also became an important goddess in Dendera, the main cult centre of Hathor.
But she was also worshipped elsewhere, especially in Koptos (in the Late Period called the Upper Egyptian Iseum) and Philae. Here her cult survived for many years, until the temple was closed down in about AD 537 by a decree of the Byzantine Emperor Justinian. It was the last pagan temple that still existed in the whole Mediterranean world.
After the conquest of Egypt by Alexander the Great in 332-331 BC the worship of Isis spread throughout the Graeco-Roman world. Several temples were built for Isis in Rome and during the reign of Caligula the Isiac festival was established. Later, temples dedicated to Isis were also built throughout Europe (including Germany and Great Britain), as well as in Africa and Asia.
Isis is mostly represented as a woman with a throne or a sun disk between the horns of a cow on her head; sometimes she is entirely in the shape of a cow. Numerous depictions (both amulets and bronze statuettes) show her with Horus on her lap. She can also have wings or be a bird entirely.