Once a great monarchy flourished and the royal Kings and Queens were buried in booby-trapped barrows with treasure and with Undead servants to watch over the tombs. Over time Wights often moved into the barrows and took them over,making them more dangerous still to those who would break in. All the same, there were those who were willing to risk themselves robbing tombs.
Three centuries passed and although some of the tombs had been robbed, more then you might expect remained intact. Things had changed, however. The religion had changed, and the monarchy was also running out of money. The currant King and his Lord Chancellor had what they thought was a great idea. The old tombs were just waiting to be raided by criminals and a few, because of the Wights within them, were a menace to passers by. So they would form an Agency, the Royal Recoverers, to open the tombs and take back the treasure into the Royal Treasury again.
The Recoverers were tattooed to prove their identity on the left arm with the symbol of a broken tomb, and given copper badges in leather wallets as well, to show their legal status, and were paid well to reduce corruption amongst them, and they broke into the barrows. Some died in the process, ensnared in cunning traps, slain by Undead servants or even ripped apart limb from limb by furious Wights, but one by one the tombs had their treasure taken.
They then were given the far less dangerous job of smashing old gravestones and in many cases, digging up the bodies to make room for farmland or urban development. Most of the bodies were burnt on great pyres, but others were thrown into the sea, thrown into a river that flowed through a neighboring country that they were having trouble with, to cause disease in that country, or sold secretly to necromancers for their own foul purposes.
The Mitrall Cult became their most feared and hated enemies and the two groups have had many bitter fights to the death.