Diocletian's Frontier Deployments

The traditional account is that the legions were joined on the frontiers by a quasi militia called limitania. These troops, drawn from the local population, would be part time soldiers and part time farmers. Their mission was twofold: First, to police the frontier lines and defend against small time brigands, and second, to act as a warning bell for the rest of the army if something bigger was on the way. The problem with all this is that though diocletian usually gets credit for introducing the limitanii into the system, these militiamen really aren't fully documented until constantine's reign. Some suspect that later historians mislabelled dioc letian's frontier deployments