This is the other starting choice for your initial Military Policy slot, (unless you play as Germany, which has an extra Military slot and will be able to use both starting Policies), and is invaluable for dealing with barbarian raiders. The +5 File:Civ6StrengthIcon.png Strength provides real edge against unruly hordes invading one's land or blocking early expansion during the early game. You should use the Policy as soon as they start turning into a problem, unless you've been lucky enough to have close neighbors who deal with the Barbarians for you. Incidentally, Discipline could be used not only in the beginning of the game (although usually later you have much better uses for your Military Policy slots).