The battle of the Tolenus or Liris River (11 June 90 BC) was a victory for the Italian rebels in which they killed the consul Publius Rutilius Lupus, although Marius, who was serving under him, partly restored the situation (Italian Social War).
Our two main sources for the battle, Appian and Orosius, give different locations for the battle. Appian places it on the River Liris, while Orosius puts in on the River Tolenus.
The Liris (modern Liri) now forms the border between Campania and Lazio. It flows into the sea just to the south-east of Minturno.
The Tolenus (modern Turano) flows north through the Appennines, starting around 30 miles to the north-east of Rome and flowing towards Rieti.
Either location is possible. The Italian leader at the battle, Vettius Scato, is previously mentions as besieging Aesernia (modern Isernia), which is close to the Liris. However Orosius and Cicero also say that Scato commanded the Marsi, which might indicate the more northerly location. Most modern accounts pick the Tolenus as the location for this battle.
Both accounts give a similar account of the battle itself. At the start of the war Rutilius had given command of one part of his army to G. Perpenna, but he suffered a major defeat and was stripped of his command. Luckily amongst Rutilius's advisors was the great general G. Marius, and he was given command of Perpenna's troops (Perpenna would continue to be given commands during Sulla's Second Civil War and the Sertorian War, and would lose almost all of his battles). Marius advised that Rutilius's men weren't ready for battle, and suggesting giving them more time to train. Rutilius didn't trust this advice, and advanced towards the enemy.
The two parts of the Roman army camped separately, not far from each other, and each built a bridge across the river, with Rutilius upstream of Marius. The Italian leader Vettius Sacto camped opposite them, on the far side of the river. His camp was nearest to Marius's, but he decided to tackle Rutilius first. Scato set up an ambush in some ravines close to Rutilius's camp, and waited for the consul to cross the river. Rutilius duly obliged, and was ambushed soon after crossing the river. The consul was wounded in the head and died soon afterwards. Many of Rutilius's men were forced back into the river. Orosius says that the Romans suffered lost 8,000 dead, including the Consul himself and many other nobles.
Marius was alerted to the disaster when bodies began to flow down the river towards his camp. He decided to try and restore the situation. He crossed the bridge, pushing aside the small covering forces that faced him, and captured Scato's lightly guarded camp. Orosius says that Marius killed 8,000 of the Marsi, balancing the Roman losses. Appian doesn’t give any casualty figures, but his does say that Scato was forced to spend the night after the battle on the site of his victory and then to retreat on the following morning due to a lack of supplies.
According to the Appian when the Roman dead were returned to the city this caused several days of mourning, and lowered morale to a worrying extend. As a result the Senate decreed that anyone who was killed in battle should be buried where they fell.
In the aftermath of the battle the Senate gave command of Rutilius's army to Marius and Q. Caepio, but Caepio was then tricked into an ambush and killed. Marius was then given command of the combined army, but he was soon forced to retire by ill health.
Vettius Scato probably disappears from our records of the war after this battle (although a P. Vettius is recorded at the battle of Mount Falernus, that was some way to the north of Scato's area of operations, and may have taken place before this battle). Seneca records the fate of a Vettius, praetor of the Marsians, who was killed by one of his slaves after being captured by the Romans, and this was probably the same man.
This is a rare example of an ancient battle with a secure date, which comes from Ovid's Fasti (On the Roman calendar). One of the entries for 11 June has the Roman Mother goddess ask Rutilius where he was rushing to, as he would be killed by the Marsians on her day, 11 June.