Ordre profond The ordre serré and the ordre profond were two ways of grouping soldiers . Historical background . Ancient origins . Historically , the ordre serré was the way of assembling soldiers in units during a battle or on the march . It is particular to infantry troops , originating in the Greek phalanx formation . Such grouping of men orientated their arms and their efforts to attack in the same direction and , combined with the hoplite s ' morale and cohesion ( reassured as they were by their comrades ' proximity ) , allowed them to defeat larger but less organised armies ( as at the Battle of Marathon ) . It was also taken up by the Kingdom of Macedon and in the Hellenistic armies before also being used by the Roman legion s and the Germans ( who fought , in the French term , " en coin " , or " in a corner " ) . Return of the ordre serré in the Renaissance . Grouping men in this way , as well as the use of the pike returned at the Renaissance ( Flanders and Swiss mercenaries ) to face royal armies with a strong tradition of heavy cavalry ( France at the battles of Courtrai and Burgundy at Grandson then Morat ) . Also , Machiavelli ( Discourses on Livy ) theorised on the use of long pikes to arm the city militias of the small merchant states of Northern Italy ( in some of which the beginnings of a citizen - body were apparent ) . The ordre serré was also used by all the armies of the Thirty Years ' War ( notably the German mercenaries ) even when they were transformed into composite formations with arquebusiers , such as the Spanish Tercio . Industrial warfare . Until the middle of the 19th century , the order and the massed impact of a column in " ordre serré " held the key to victory . The order " " Serrez les rangs ! " " was thus the main order to marching units to give battle to the enemy despite their losses . Then the development of firearms and cannon made definitive changes to battle formations - from then on , " firepower kills " was the order of the day . It decimated the columns of the Crimean War , the American Civil War and the Franco - Prussian War . From then on , the ordre serré was only used for riot control ( CRS and Gendarmerie mobile ) , or to order and move large bodies of men , or for parades ( notably that on Bastille Day ) . Use of the ordre serré . Concepts . In the 18th century , a fierce debate arose among tacticians , some backing the ordre serré and some backing the ordre profond . Infantry fighting thus based itself on two concepts : The English preferred the " ordre mince " ( thin order ) and had even developed salvo firing by sections , which allowed a group of men to ( on each volley ) create a gap in the opposing formation . Less professional armies used salvoes in line - formation , with three ranks ( having one rank fire while the other two reloaded ) . The losses to each salvo were divided up amongst the mass of the opposing unit , and thus had a less damaging effect on morale than fire by section . The French armies of the 18th and early 19th centuries placed a significant amount of emphasis on the ordre profond , in part to counter the success of the English and Prussian " ordre mince " . The ordre profond was also appealing in that , at least on paper , it would cure the problems with desertion , decisiveness , and systematizing that the French had experienced throughout the 18th century , particularly in the 7 Years War . The ordre profond , with its roots symbollically in the Roman legion and the Greek phalanx , also had a degree of romantic appeal . Depictions of French soldiers as the hoplites holding pikes rather than muskets were common . Most important for the development of the ordre profond in 18th century France was the belief in the universal principles of war . Many tacticians believed that warfare could be conducted according to rules as applicable in contemporary society as they were in antiquity . Thus , many writers rejected technological change as a reason to change battlefield tactics , emphasizing the importance of depth and shock over firearms . This belief continued into the 19th century , and arguably beyond Formations . Different formations arose due to new technologies on the battlefield and new concepts as to their use :