Marcus Claudius Marcellus was Roman consul for year 166 BC (together with Gaius Sulpicius Gallus), for 155 BC (with Publius Cornelius Scipio Nasica Corculum), and for 152 BC (with Lucius Valerius Flaccus).

In 155 BC, he celebrated a triumph against the Apuani. In 152 BC he assumed his third Consulship and replaced the previous Consul, Quintus Fulvius Nobilior, in his command against the Celtiberians in Spain.

Having arrived with reinforcements, he negotiated the surrender of Ocilis and defeated the Nergobriges, before they and the other Celtiberian tribes of the Arevaci, the Belli, and the Titthi, sued for peace with Rome. Marcellus sent ambassadors back to the Senate in Rome, urging them to accept the peace proposals and end the long war in Spain. The Senate however, refused and began gathering a new army to be again sent to Spain the following year, appointing Lucius Licinius Lucullus, Consul-Elect for 151 BC, to replace Marcellus once his term as Consul expired.

Upon learning of this, Marcellus nevertheless remained resolved to make peace in Spain and end the war before Lucullus' arrival. However, the Arevaci then attacked Nergobriga, the city of Nergobriges, and broke the truce agreed with Marcellus. In retaliation, the Romans marched to besiege the Arevaci capital of Numantia, however, before the assault could begin, the Numantines re-opened negotiations for peace and, in a conference with Marcellus, the Numatine leader, Litenno, offered that the Arevaci, Belli and Titthi would once again agree to make peace with Rome. Delighted, Marcellus accepted the offer and, the tribes having handed over the required hostages and money as guarantees that they would not break their promise, concluded the war in Spain before Lucullus and his army arrived.

He founded Corduba (Cordoba) sometime in the 160s or 150s.

Barn:
Marcellus av Claudii, född -170, död -120