Emperor Septimius Severus defeats usurper Clodius Albinus in the Battle of Lugdunum, the bloodiest battle between Roman armies.

Lucius Septimius Severus was Roman emperor from 193 to 211. He was born in Leptis Magna, Libya in the Roman province of Africa. As a young man he advanced through the customary succession of offices under the reigns of Marcus Aurelius and Commodus. Severus was the final contender to seize power after the death of the emperor Pertinax in 193 during the Year of the Five Emperors.

Roman usurpers were individuals or groups of individuals who obtained or tried to obtain power by force and without legitimate legal authority. Usurpation was endemic during the Roman imperial era, especially from the crisis of the third century onwards, when political instability became the rule.

Decimus Clodius Albinus was a Roman imperial pretender between 193 and 197. He was proclaimed emperor by the legions in Britain and Hispania after the murder of Pertinax in 193. Initially Albinus cooperated with another contender for the throne, Septimius Severus, but the two turned on each other in 196 and commenced a civil war. Albinus died in battle the following year.

The Battle of Lugdunum, also called the Battle of Lyon, was fought on 19 February 197 at Lugdunum, between the armies of the Roman emperor Septimius Severus and of the Roman usurper Clodius Albinus. Severus' victory finally established him as the sole emperor of the Roman Empire following the Year of the Five Emperors and immediate aftermath.

February 19 is the 50th day of the year in the Gregorian calendar; 315 days remain until the end of the year.