The ostrich feather is the emblem of the Egyptian Goddess embodying justice, Ma’at. Egyptians believed that at the time of death, the feather was weighed against the heart of the deceased.
A heart made heavy by sin outweighed the feather and was devoured by the monster Ammit, but a light heart meant the individual was free from sin and entitled to join Osiris in the underworld. (The origin of the phrase “light hearted.”)
The feather of Ma’at was adopted as a personal emblem of rock musician Robert Plant for use on the Led Zeppelin album “Four.”