outside the ritual boundaries () of towns and cities. Grand monuments and humble tombs alike lined the roadsides, sometimes clustered together like "cities of the dead". Tombs were visited regularly by living relatives with offerings to the deceased of food and wine, and special observances during particular Roman festivals and anniversaries; with correct funerary observances and continuity of care from one generation to the next, the shades of departed generations were believed to remain well disposed towards their living descendants. Families who could afford it spent lavishly on tombs and memorials. A Roman sarcophagus could be an elaborately crafted artwork, decorated with relief sculpture depicting a scene that was allegorical, mythological, or historical, or a scene from everyday life. Some tombs are very well preserved, and their imagery and inscriptions are an important source of information for individuals, families and significant events. Care of the dead In Greco-Roman antiquity, the bodies of the dead were regarded as polluting. At the same time, loving duty toward one's ancestors () was a fundamental part of ancient Roman culture. The care of the dead negotiated these two emotionally opposed attitudes. When properly honoured with funeral rites and memorials by the living, the spirits of the dead were thought to become benevolent ancestors and protect their descendants. Those who died "before their natural term" or without proper funeral rites were thought to wander the earth, and haunt the living as vengeful, vagrant ghosts (Lemures). In Horace's Ode 1.28, the shade of a drowned, unburied sailor, trapped through no fault of his own between the worlds of the living and the dead, implores a passer-by to "sprinkle dust three times" on his corpse and give him rest, or suffer his revenge. Cicero (Laws 2.22.57) writes that "... until turf is cast upon the bones, the place where the body is cremated does not have a sacred character...." The ritualistic casting of earth or placing of turf on the cremated bones might have been the minimum requirement to make a grave a locus religiosus (a religious place, therefore protected by the gods). Burial rites, and burial itself, could be denied to certain categories of criminal after execution, a demonstration that through this simple omission, the power of the state could extend to the perpetual condemnation of souls. Rome had a high mortality rate, and disposal of the dead was an essential, practical and often urgent obligation