Brand. Pr Nefrt raw .polyston Canopic jars used by the ancient Egyptians during the mummification process to store and reserve the viscera of their owner for the afterlife. They were commonly either carved from limestone or were made of pottery. These jars were used by the ancient Egyptians from the time of the Old Kingdom until the time of the Late Period or the Ptolemaic Period, by which time the viscera were simply wrapped and placed with the body. The viscera were not kept in a single canopic jar: each jar was reserved for specific organs. The name "canopic" reflects the mistaken association by early Egyptologists with the Greek legend of Canopus. Canopic jars of the Old Kingdom were rarely inscribed and had a plain lid. In the Middle Kingdom inscriptions became more usual, and the lids were often in the form of human heads. By the Nineteenth dynasty each of the four lids depicts one of the four sons of Horus, as guardians of the organs.