In the 7th century, St.Cuthbert of Northumbria petitioned the Pope to allow burials on church grounds. Church grounds are considered “consecrated,” meaning the land is set aside and dedicated to those who serve God. Consecrated ground is sacred, and it is believed that burial inside it will bring your soul closer to Heaven. Church grounds that allowed burials were called “churchyards,” and soon after Cuthbert's request was granted, began to be referred to as “graveyards.”
It wasn’t until the eighth century that the consecration of all burial sites became customary. If open ground is to be considered consecrated, it must be set apart somehow from the common, and it's boundaries have to be easily identified. These boundaries are usually marked with large stones, walls, or fences. Burial grounds that are enclosed and defined in such away, and are NOT located on church grounds are called, “cemeteries.”
There is another condition that must be met before a plot of ground is considered consecrated. That is, the grounds must be continually maintained. If a cemetery becomes overgrown and abandoned, it is no longer considered consecrated. The same is true for churches and church grounds; once abandoned, overgrown, and derelict, they are no longer dedicated to the service of God, and are therefore no longer considered sacred.
To the Romans, the only honorable way of handling one’s remains was to cremate them. Being buried in the ground was a sign of disrespect, and reserved only for criminals and persons committing suicide. Since Christians were considered criminals, they were not allowed the honor of cremation; instead, they too were buried, and their graves marked, as a sign of disrespect.
Ironically, what began as the Roman's outward sign of disrespect remains the customary Christian tradition. Christians continue to bury their dead and mark their gravesites, and to many- cremation is considered unholy.