The ancient Egyptians connected the two events and so, over time, Sopdet took on the aspect of a Goddess of not only the star and of the inundation, but of the fertility that came to the land of Egypt with the flood. The flood and the rising of Sirius also marked the ancient Egyptian New Year, and so she also was thought of as a Goddess of the New Year, and later was linked to the pharaoh and his journey in the afterlife.
Although Sopdet started out as an agricultural Goddess, closely associated with the Nile River, by the Middle Kingdom she was also considered to be a mother Goddess. This probably related to her growing connection with the Mother Goddess Isis. This connection was further strengthened by Sopdet´s role in assisting the Pharaoh find his way to the imperishable stars. It may be no coincidence that Sirius disappeared for 70 days every year, and mummification took 70 days.
In the First Dynasty ivory tablets Sopdet was depicted as a reclining cow with a unidentified plant-like emblem (possibly signifying representing the new year) between her horns. However, she was most often depicted as a woman wearing the white crown of Upper Egypt topped by a star or a headdress with two plumes. Less often, she is portrayed as a large dog, and by the Roman period the hybrid Goddess Isis-Sopdet was depicted as a woman riding side-saddle on a large dog.
Sopdet was occasionally shown as a male deity. During the Middle Kingdom the male Sopdet was in associated with Horus as one of the Gods who held up the four corners of the earth and held Nut (the sky) in place. During the Greek period she was linked to Anubis as Sopdet-Anubis, possibly because of her canine associations.
Sopdet is also linked with other Goddesses including Isis, Hathor and Bast.
*The inundation of the Nile River occurred from July to September prior to the construction of the Aswan Dam in 1970.
Source: Ancient Egyptian Online