Lucius Junius Caesennius Paetus (c. 20 - 72?) was a Roman aristocrat, member of the gens Caesennian and Junian, who lived in the second half of the 1st century during the Roman Empire. He was Consul Ordinarius for the year 61, and enjoyed several high provincial commands in the East.
Paetus was the son of Publius Caesennius Paetus, born c. 5 BC, a Tarquinian Etruscan Italian; paternal grandson of Caesennius, born c. 40 BC; and great-grandson of Lucius Caesennius Lento.
Paetus served as a Roman politician and general during the reigns of Roman Emperors Nero (54-68) and Vespasian (69-79). He served as a Consul Ordinarius in 61. After his consulship and in the same year, perhaps in June, Paetus was appointed Governor and Legatus Augusti pro praetore of Cappadocia. During his governorship, the General Gnaeus Domitius Corbulo was conducting Rome’s war with Parthia over Armenia. In successive campaigns, Corbulo had established Roman rule over the country, and Paetus was placed in charge of defending it from Parthian counterstrokes.
Paetus despised Corbulo’s talent as a general. In 62 however, Paetus, at the head of the legions XII Fulminata and IV Scythica suffered a catastrophic defeat at the Battle of Rhandeia against the Parthian and Armenian forces of King Tiridates I of Armenia. Although relief forces headed by Corbulo were only 50 miles away, Paetus surrendered his fortified camp. He and his legions were shamed by passing under the yoke and were allowed to retreat from Armenia. After his defeat, Paetus' weak character and his incapability to command were revealed, and his military command was entrusted again to Corbulo. Charged with both incompetence and cowardice, Paetus was quickly pardoned by Nero, who dismissively commented that suspense would be harmful to someone of such timidity.