In ancient Rome runaway slaves were marked with "FUG" on their foreheads.
In Rome a runaway slave could not legally be the object of sale. A class of persons called Fugitivarii made it their business to recover runaway slaves. The rights of the master over the slave were in no way affected by his running away. Runaway slaves were branded or tattooed on the forehead with letters denoting the slave as a runaway (FUG) which was an abbreviation of "fugitivus," meaning "runaway".