Mummy brown was a rich brown bituminous pigment, intermediate in tint between burnt umber and raw umber, which was one of the favorite colors of the Pre-Raphaelites.
Mummy brown was originally made in the 16th and 17th centuries from white pitch, myrrh, and the ground-up remains of Egyptian mummies, both human and feline, one London colourman claiming that he could satisfy the demands of his customers for twenty years from one Egyptian mummy.
It fell from popularity in the early 19th century when its composition became generally known to artists. According to Jasmine Day, in her book The Mummy’s curse: Mummymania in the English-speaking World, “In 1881, the artist Laurence Alma Tadema, famous for his romantic ancient Egyptian scenes (such as that above which is very … brown), saw his paint preparer grinding up a piece of a mummy. Realizing where “mummy brown” came from, he alerted his fellow painter, Edward Burne-Jones [and] together with some family members, the remorseful artists held an impromptu funeral burying a tube of mummy brown paint.” [Source]