Answer: oriflamme

AnswerCrossword Clue
ORIFLAMMEBanner that serves as a rallying point
oriflammeA principle or ideal that serves as a rallying point in a struggle
oriflamme(in historical use) A scarlet banner or knight's standard
oriflammean inspiring standard or symbol; the orange-red flag of the Abbey of St. Denis, used as standard by the early kings of France