First proposed by the French theorist Comte de Guibert, the Mixed Order could be adapted to be used by companies or battalions and involved two or more of these units using a combination of Line and Column formations. Its origins were in the revolutionary wars where the massed French militias lacked the training and experience to complete complicated manoeuvres and by necessity adopted a mixed order of veteran trained units and newly recruited/conscripted units. The regular troops moving in line along with the recruits moving in column, which required far less training to perfect, either on the flanks, the centre or in the rear of the veteran units.
The column formation allowed the unit rapid movement, a very effective charge (due to weight of numbers) or it could quickly form an infantry square to resist cavalry attacks, but by its nature only a fraction of its muskets would be able to open fire. The line offered a substantially larger musket frontage allowing for greater shooting capability but required extensive training to allow the unit to move over ground as one while retaining the line.
The mixed order remained a part of French tactical doctrine as the French army grew in discipline, capitalising as it did on the strengths of both the line and column formations, while avoiding some of their inherent weaknesses. It was used extensively by Napoleon when commanding the Grande Armée.