Osiris' soul, or rather his Ba, was occasionally worshipped in its own right, almost as if it were a distinct god, especially in the Delta city of Mendes. This aspect of Osiris was referred to as Banebdjedet, which is grammatically feminine (also spelt "Banebded" or "Banebdjed"), literally "the ba of the lord of the djed, which roughly means The soul of the lord of the pillar of continuity. The djed, a type of pillar, was usually understood as the backbone of Osiris, and, at the same time, as the Nile, the backbone of Egypt.
The Nile, supplying water, and Osiris (strongly connected to the vegetable regeneration) who died only to be resurrected, represented continuity and stability. As Banebdjed, Osiris was given epithets such as Lord of the Sky and Life of the (sun god) Ra, since Ra, when he had become identified with Atum, was considered Osiris' ancestor, from whom his regal authority is inherited. Ba does not mean "soul" in the western sense, and has to do with power, reputation, force of character, especially in the case of a god.
Since the ba was associated with power, and also happened to be a word for ram in Egyptian, Banebdjed was depicted as a ram, or as Ram-headed. A living, sacred ram was kept at Mendes and worshipped as the incarnation of the god, and upon death, the rams were mummified and buried in a ram-specific necropolis. Banebdjed was consequently said to be Horus' father, as Banebdjed was an aspect of Osiris.
Regarding the association of Osiris with the ram, the god's traditional crook and flail are the instruments of the shepherd, which has suggested to some scholars also an origin for Osiris in herding tribes of the upper Nile. The crook and flail were originally symbols of the minor agricultural deity Andjety, and passed to Osiris later. From Osiris, they eventually passed to Egyptian kings in general as symbols of divine authority.
The cult of Osiris continued until the 6th century AD on the island of Philae in Upper Nile. The Theodosian decrees of the 390s, to destroy all pagan temples, were not enforced there. The worship of Isis and Osiris was allowed to continue at Philae until the time of Justinian I, by treaty between the Blemmyes-Nobadae and Diocletian. Every year they visited Elephantine, and at certain intervals took the image of Isis up river to the land of the Blemmyes for oracular purposes. The practices ended when Justinian sent Narses to destroy sanctuaries, arrest priests, and seize divine images, which were taken to Constantinople.