TheBattle of Solicinium was fought in 368 between theRoman army, led byEmperorValentinian I, and an army ofAlamanni invading the province ofGaul. The Romans managed to repel the Alamanni but suffered heavy losses during the battle.

Battle of Solicinium
Part of the Roman–Alamanni conflict andRoman–Germanic Wars
Neckar watershed closer
Date 368 AD Location Southwest Germany, south of the Limes Result Roman victory
Belligerents
Roman Empire	Alamanni
Commanders and leaders
Valentinian I Sebastianus	Rando
Casualties and losses
Heavy	Unknown

After the death ofJulian inPersia in 363, theAlemans, forgetting the treaty of truce which the emperor had extorted from them after his four successful campaigns beyond theRhine (in 357, 358, 359, and 360),^[1] renewed their incursions intoGaul, alleging as the pretext for war the contempt ofValentinian I's ministers in failing to supply them the accustomed tribute. In the year 366 they crossed the Rhine, and after amply compensating for the remission by the plunder which they secured, retired beyond the river. The next year, when they repeated their expedition, they found the Romans prepared, for Valentinian had crossed theAlps to secure the threatened province. However, in two successive battles, they defeated his generals, signalizing their victory by the capture of several standards. The enraged emperor, after restoring by a severe sentence the discipline of the legions, entrusted the command toJovinus, an able officer who soon proved his qualification for the appointment by the total discomfiture of the invaders. After defeating two separate detachments of the Alemani along theMoselle, he met the united forces of the nation atChalons-Sur-Marne and amended the disgrace of the previous defeat by routing the enemy, who suffered losses of up to 10,000, as opposed to no more than 1,200 of the Romans. The remnant was driven over the Rhine, and Jovinus, after retiring toParis for the winter, received the honours of theconsulship for the next year as the reward of his success.^[2]

The celebrations for Jovinus' victory were soon interrupted by the intelligence of new disasters.Rando, a barbarian chieftain, in early 368 fell unexpectedly on the town ofMoguntiacum (modernMainz) on the Rhine, and put the defenceless inhabitants to the sword, before retiring over the river. Valentinian, furious, now determined to anticipate their future depredations by a campaign into their own territory beyond the Rhine. CountSebastian was deputed to encircle the enemy from the south, by way ofRhaetia, while the emperor himself advanced with the entire forces of the west from Gaul. Finding their arms inadequate for the defence of their fields and villages, the Alemans retreated into the mountains, erecting their camp on an unidentified hill referred to as "Solicinium", in the area ofWürttemberg.

It is reported that the emperor, while on a personal reconnaissance of the enemy position on the lower reaches of the mountain, was nearly captured by an advanced party of the enemy who had been placed in ambuscade, losing his helmet and standard-bearer while retreating.

There is little known about the actual battle. It appears that Valentinian carried their defenses by a general assault, charging up the slope, and the barbarians, when they were ejected from the summit, were driven down the opposite side of the hill into the clutches of Sebastian, who had been placed in their rear to anticipate the retreat. The result was the total defeat of the Alemans.^[3]

The actual location of the battle is not known and remains subject to historical speculation and disagreement. No archaeological evidence has been found so far and many of the hills in the region could be the actual site of the battle. The locations under consideration areSulz am Neckar,Heidelberg,Schwetzingen,Rottenburg (Sülchen),Glauberg or theSpitzberg nearTübingen. All these sites are located in southwestern Germany, but spread over an area of roughly 200 km in diameter. The most recent research shows that the battle probably took place in the northern part of what is todayHechingen, and the lost city of "Solicinium" was located where the Roman museum of Hechingen is located today.^{[citation needed]}

• Gibbon, Edward,The Decline And Fall Of The Roman Empire, (The Modern Library, 1932), chaps. XIX., XXII., XXV.