In ancient Greece dogs were wearing similar collars to the spike-studded ones their medieval successors are wearing. A sheepdog, which had to be white in order to be visible at night, was given a mellium (a leather collar studded with nails). One of the main purposes of wearing a collar was a protection of dogs furry neck from the bite of a wolf. Like 21st century dog owners, Greek farmers preferred their dogs to be fierce, but not overly aggressive. They had to be tough enough to attack intruders but friendly enough not to turn on their handlers. It is very interesting to note that while the sheepdogs had to be white, the farmhouse dogs had to be black — so they could have more stealth and conceal themselves better to surprise intruders.