Classe was a military port located 4 km (2.5 mi) east south east from Ravenna, Italy. It was near the head of the Adriatic coast. For almost five hundred years it was an important strategic military port. When it was not being used as a military port, it was an important commercial port for the imperial capital of Ravenna in the Roman Empire. Classe comes from the Latin word classis, meaning fleet.
There was a small port and harbor for commercial trade. The city of Ravenna, north of the harbor, was founded in the late 3rd or early 2nd century BC.
Sometime between 35 and 12 BCE, Octavian (later known as Augustus) established Ravenna's harbor as one of the home ports for his new Roman navy. South of the harbor, the area was occupied mainly by cemeteries, but by the 2nd century AD a town, later known as Classe, had grown up.
Augustus may have chosen this site because of its strategic position. The area in which Augustus wanted to construct Classe was in a lagoon. It was impregnable from land and surrounded by marshes. The base was artificially constructed in this lagoon. Unlike the ports of Portus or Ostia, Classe did not feature a hexagonal basin. Instead the base installations were built on stilts. Once those were in place the port was made of large oak beams. By the 1st century CE the builders had incorporated ceramic fragments. By the 2nd century, it was redone with bricks. Augustus designed the port for military purposes only. The town had only one weakness, access to fresh water. This obstacle was overcome by the Emperor Trajan who built a 35 km (22 mi) long aqueduct to Ravenna, that might also have supplied Classe. After the fleet was built, the population of the soldiers and their families living there grew slowly but steadily. For the next three hundred years, Classe would be one of Rome’s most important naval bases, the home of the eastern Mediterranean fleet The 3rd-century historian Cassius Dio states that the fleet had two hundred and fifty ships. This is the only account that survived to this day and it is only because it was quoted by Jordanes, a 6th-century historian.