The minimum requirement for veneration offered to the dead is probably some kind of belief in an afterlife, a survival at least for a time of personal identity beyond death. These beliefs are far from uniform.
Early Christianity's attitudes toward, practices in connection with, and festivals of the dead
Many early Christians were persecuted for their faith, leading many Christians in Rome to hide in the catacombs. As a result, they found themselves praying and worshipping God surrounded by the tombs and bodies of the dead. When possible, they sought to pray among the bodies of dead Christians, sometimes using a coffin or tomb for an altar on which to celebrate the Eucharist. Sometimes they witnessed miracles in connection with the bodies of dead Christians, such as healing, or observing sweet-smelling myrrh exuding from their bones. This, combined with their belief in the Resurrection of Jesus Christ and future resurrection of all Christians, eventually led to the veneration of saints and of their relics. Early accounts of martyrs include Christian witnesses making great efforts to obtain the remains of the martyrs, and of the Romans sometimes trying to prevent this. Also, it became common to continue to ask Christian leaders to pray for them, even after the leaders had died, as they believed that these Christians were still able to pray and that their prayers would still be effective.
Catholicism's attitudes toward, practices in connection with, and festivals of the dead
See All Saints Day, Saint, Day of the dead
See "Hsiao" in Confucianism
see also History of Egypt
Chinese attitudes toward, practices in connection with, and festivals of the dead
Egyptian attitudes toward, practices in connection with, and festivals of the dead
The ancient Egyptian pyramids are the most famous historical monuments devoted to the dead (see Great pyramid of Giza). Egyptian religion posited the survival of the soul in connection with the survival of a physical receptacle for the soul - hence mummification and portraiture flourished.Roman attitudes toward, practices in connection with, and festivals of the dead
The ancient Romans, like many Mediterranean societies, had strong prohibitions against dead bodies. Bodies of the dead were often displayed for a time, but were then taken outside the pomerium or sacred boundary of the City - in effect, the City walls - for cremation. Ashes and bone fragments were then interred outside the walls. Aristocratic Romans had from their remote past observed the custom of keeping portraits of their male ancestors - they had probably borrowed this custom from the Etruscans. These portraits were originally in the form of masks - probably even death-masks moulded on the dead ancestor's face. On significant family holidays the living members of the family might wear the masks in procession. In the 2nd century A.D. practices shifted from cremation to burial. The reasons for this change are not at all clear. Scholars have posited influences from groups who practiced burial - for instance, the increasing numbers of Germanic foederatii (troops settled inside the borders of the empire) - and from the increasing numbers of practitioners of religions that practiced burial for doctrinal reasons, like Judaism, Christianity, and the Egyptian syncretistic Mystery religions.