Montjoie Saint Denis!

Montjoie Saint Denis! was the battle cry and motto of the Kingdom of France.

It allegedly referred to Charlemagne's legendary banner the Oriflamme, which was also known as the "Montjoie" (Old French: Munjoie) and was kept at the Abbey of Saint Denis, though alternative explanations exist (see below).

The battle-cry was first used during the reign of Louis VI of France (r. 1108–1137), the first royal bearer of the Oriflamme.

Etymology of "Montjoie"
The etymology of the term "Montjoie" is uncertain. It is first recorded in The Song of Roland (12th century). The Catholic Encyclopedia suggested it originated in a term for marking stones or cairns set up on the roadside, in Late Latin known as mons Jovis, which from c. 1200 in French appears as monjoie. According to the Encyclopedia, cairns were used by warriors as gathering places and was applied to the Oriflamme by analogy in that it guided warriors into combat like they would meet by said cairns.

"Montjoie" has also been proposed as being derived from a Germanic source, mund gawi ("pile of stones"), supposedly used as a battle cry in a sense of "hold the line!". It has alternatively been proposed as deriving from mund galga, from mund "protect" and galga "cross, rood" (as pilgrims would often affix crucifixes to these stones). Charles Arnould claimed the word originated in Gaulish mant- "path" and gauda "pile of stones".