Battle of Leuctra
Use of the formation dates back to ancient infantry and cavalry warfare, as an alternative to column, line-abreast, or phalanx (box) formations. One of its earliest uses was at the Battle of Leuctra, when the Thebans attacked the Spartan right with a column 48 men deep while their weaker center and right were repelled. The echelon formation may have been used by Hannibal at the Battle of Cannae, Alexander the Great at the Battle of Gaugamela, Frederick II of Prussia, and the Confederate army at the Battle of Gettysburg.