The origins can be traced to Constantine in AD 312. The form of the ringed cross became very important, and it was carved onto the surface of gravestones as a symbol. The gravestones of Irish immigrants in California, though, are found to be much different from their Irish counterparts, and they are also found to show more variation amongst themselves. Apparently, the traditional mortuary art motifs lost some of their value for the Irish immigrants. Among other things, my study has shown the value of studying mortuary artworks as archaeological material.
Gravestones relate a wealth of cultural information.
Furthermore, gravestones are associated with ideological concepts of death, and these concepts are very important for our understanding of cultures both past and present.