This battle needed to be remade, as the original was of poor quality but had a good idea behind it. So let's dig into this.
Gaius Julius Caesar was a Roman statesman, general and dictator of the Roman republic. Caesar spent the majority of his career as a politico, becoming governing of most of northern Italy after his term of Counsel. He would fighting a campaign in Gaul from 59 BC to 51 BC before fighting in a civil war against a large number of political rivals from 50 to 45 BC. Caesar would act as dictator of Rome for a brief time before being assassinated in 44 BC.
Gladius Hispaniensis: A relatively long variant of Gladii, being around 2 ½ feet long. The weapon had a decent balance, being in that strange middle ground between high impacts and good blade control, not being great or bad at either. The sword was primarily a thruster but was also a decent cutter.
Pilum: A javelin with a relatively large length, being roughly 2 meters in length overall. The deadly bit was composed of a soft iron shaft and a hardened tip. This point of the Pilum was to be thrown at only a few yards, with the shaft warping on impact and getting lodged into an enemy's shield, that is if it didn’t skewer the man holding it.
Pugio: A short dagger, being around 10 inches long. The weapon had a wide and double edged blade with a fine point. It was fine for both cuts and thrusts, though it lacked any impact due to its small size. It was mainly used if Gladius was lost.
Charlemagne was a Carolingian King and later emperor of the Holy Roman Empire. He was born son of Pepin the short, and became king in 771 AD. He would spend most of his time as king fighting all the surrounding kingdoms and spreading Christianity overall these newly conquered lands. In 800, he would become Emperor of the Holy Roman Empire by Pope Leo III. He would die in 814 AD from medical complications.
Migration period sword: A long slashing sword, being around 3 feet long in total. The weapon had a more blade heavy balance, giving it a higher impact but lower level of liveliness in the hand, lacking pretty much any form of tapering. The sword was a mighty great cutter, sporting a very blade heavy balance.
One handed spear: A one handed spear used in tandem with a shield, being some 6 feet long . The weapon was often composed of an ash, pine or oak shaft and an iron or steel head. The spear was designed to keep enemies with short weapons at arm's length, being used to beat and chip away at the enemies lines until one side is weak enough to be rushed.
Seax: A type of common work knife, being a foot in length. The Seax was made of either iron or steel, having a single edged blade. The blade, while not designed for combat it could still easily be used to kill.
Caesar: During his time as a military commander, Caesar fought in 2 back to back campaigns, those being the Gallic campaign and Caesar's civil war. In the former, Caesar fought a number of smaller scale campaigns against handfuls of singular groups, taking down each group who could oppose him. This ended with the battle of Alesia, where he finally defeated the Gallic king Vercingetorix. This was followed up by his conflicts with all his opponents in the senate, primarily conflicting with Cato the younger and more Pompeii Magnus. After his Civil war, Caesar would be dictator for life and wouldn’t lead another campaign.
Charlemagne: Charlemagne spent large amounts of his life at war. Before becoming king of Frankia, he aided his father Pepin in several small military campaigns. After accession to the throne, Charlemagne would go about fighting in most of western Europe. He would first push south, retaking lost territory near the Pyrenees and making contact with the Moors living in Spain. After this he would begin conflicts in Northern Italy against the Lombard, later pushing farther south past the city of Rome. He would push each into Bavaria along with pushing well north into Saxon lands, absorbing the area and committing small scale genocide upon the pagans of the area.
Caesar: Being a post Marian reforms general, Caesar led an army of professionally trained soldiers. These Legionaries were professionals, having gone through extensive physical training, with all being incredibly well drilled, physically hardened and disciplined. Each man would go through 4 months of hellish training, learning how to march, their tactics, the usage of weaponry, and how to respond to orders. The men who followed Caesar were some of the toughest alive at the time, with many having spent over a decade following Caesar around the Mediterranean.
Charlemagne: Due to the Franks not maintaining an extensive standing army, most of Charlemagne's men were armed and trained peasant levies. These Frank’s, when war would be declared, would be called to muster. They would then be equipped and given several weeks of harsh basic training. Beyond this, most men would gain their skill through live combat and experience. The skill of these men would vary however, with some being young farmers with little experience and others being veterans who’d survived previous campaigns.
Caesar: During the time Caesar was active, Roman legionaries were most dressed in mail. At the time, most would be dressed in a set of mail armor known as Lorica Hamata. This mail would cover most of the torso, upper arms and the upper thighs, with double layers over the shoulders. This would be worn over a Subarmilis, a type of sleeveless padded shirt. These men wore Galea helmets, specifically of the Montefortino variety, usually being made from Bronze. The most iconic type of armor would’ve been the Scutum, a large rectangular shield with a horizontal center grip.
Charlemagne: During the time Charlemagne was at his peak, many of his men would be dressed in mail. At the time, most of his men would’ve been given a mail shirt which covers the torso, upper thighs and arms down to the elbow. Most of these constructs would have worn a type of conical helm made from iron, some of which had a nasal or mail aventail along the back. Many of these men also would've carried a center grip round shield with an iron boss (if I'm missing something, pls tell me).
Caesar: Legionaries had a very specific type of tactic which was based around fighting the common type of shield wall used by most Celtic armies at the time. When engaging, the section of soldiers would usually start out using a Testudo to close into melee (won’t play into match) combat before opening up. When within close range, only about 3-4 yard, they would then throw their heavy Pila, before immediately drawing swords and closing the gap as a singular unit and entering close combat.
Charlemagne: Frankish warriors primarily fought using a traditional shield wall formation similar to most infantry based armies at the time. These walls would generally be a relatively wide line of men, all carrying shields and spears and keeping at the edges of the spears range. They would then commence a match of chipping and picking away at the enemies until one side was weakened enough to be prone to a charge. From here, these men would drop spears and take up side arms like swords before closing the gap and engaging in close quarters, generally leading to the enemies being routed.
The fight between these two will be a mostly close range engagement, with neither side having dedicated ranged support. The fight will be a 10 on 10, with the sides being composed of 10 men. Among these men will be the overall commanders (Caesar and Charlemagne), an advanced soldier (A Centurion and Veteran Lieutenant) and 8 grunts (Legionaries and Levies). The battle will be fought in a small field, with both sides starting only 35 feet away. Commanders won’t likely engage unless the situation is truly necessary. Both Caesar and Charlemagne will be mounted.