The Roman Legion consisted of 6100 infantry and 726 cavalry, divided into the Militarain Cohort of 1105 heavy foot, 132 Cuirassiers and nine ordinary Cohorts, each containing 555 heavy foot and 66 Cuirassiers. The Legion was drawn up in three lines; the first of which was termed Principes, the second Hastati, and the third Triarii. The infantry were protected by helmet, cuirass, greaves and shield; their arms were a long sword, a short sword, five javelins and two large spears. With this formation Caesar over-run Spain, Gaul, Germany, Britain, Africa, Greece, and Italy. The Scots alone withstood him and the ruins of a triple line of Roman entrenchments extending from the North to the Irish Seas to this day mark the southern boundary of the Scottish Highlands and the northern limit of Roman dominion. At Pharseleus, Pompey made the inexplicable blunder of placing his best troops in his right wing, which was covered by the river Enipeus and inferior troops on his left wing which was in the air. By its first charge, the Tenth Legion destroyed the latter, outflanked the entire Pompeian army, drove it backward into the river and single handed won for Caesar undisputed dominion of the Earth. * * * * * The _Scots Volunteers_ of Gustavus Adolphus consisted of two brigades aggregating about 12,000 foot, made up of Scottish gentlemen who for various reasons were attracted to the Continental Wars. At Leipsic, (Sept. 7, 1631) 20,000 Saxons, constituting one-half of the allied Protestant army, were routed at the first charge, put to flight and never seen again. Tilly’s victorious right wing then turned upon the flank of the King’s army. Three regiments of the Scots Volunteers on foot held in check in open field 12,000 of the best infantry and cavalry in Europe, until Gustavus had destroyed the Austrian main body and hastened to their aid with the Swedish heavy cavalry. The Castle of Oppenheim was garrisoned by 800 Spanish infantry. Gustavus drew up 2,000 Swedes to escalade the place. Thirty Scots Volunteers, looking on observed that the Spaniards, intently watching the King had neglected to guard the opposite side of the fortress. Beckoning to their aid about a hundred of their comrades, they scaled the wall, captured the garrison and opened the gates to the king. Gustavus entered on foot, hat in hand. “My brave Scots,” said he, “you carry in your scabbards, the key to every castle in Europe.” * * * * * The _Van-Guard_ of Frederic the Great is the perfect adaptation of the minor tactics of Epaminondas to gunpowder. This choice body was made up of the best troops in the army divided into infantry, cuirassiers, dragoons and light artillery. The Van-Guard, a miniature army in itself, always marched between the main body and the enemy; it always led in the attack, followed by that wing containing the best soldiers, in two lines; and supported by the heavy cavalry on that flank.