Why is a heart left in place of a mummy?

In ancient Egyptian culture, the heart was considered the seat of intelligence and emotion, as well as the center of a person's being. During the mummification process, the heart was often left in the body or placed back inside after preservation, as it was believed to be essential for the deceased's journey in the afterlife. It was thought that the heart would be weighed against the feather of Ma'at during the judgment of the dead, determining the individual's fate in the next world. This practice underscored the heart's vital role in both life and the afterlife.