Caesarea was actually the name of three separate cities: one in Palestine, one in Cappadocia (Asia Minor), and one in Mauretania, present day Algeria. The first city, Caesarea Palestinae, was built by Herod around 25 BCE and like the other two cities was named for Emperor Augustus. It served as an administrative capital for the province, and in the 8th century CE, the Emperor Vespasian made it a colonia. The city would later become the capital of Judea.
Lastly, originally named Iol, Caesarea Mauretania lay along the northern coast of Africa near the present day city of Algiers. It was originally founded by the Phoenicians in the fifth century BCE to serve as a trading station. During the 3rd century BCE, due to Caesarea Mauretania’s strategic location, new defences were built, and in 33 BCE. Rome annexed the area, placing it in the hands of a Nubian prince named Juba II. Although his father was once an ally of Pompey, Juba had lived in Rome under the tutelage of Julius Caesar, learning to read and write Greek and Latin. As he was considered too Roman to rule, Juba and his wife, Cleopatra Selene (the daughter of Pompey and Cleopatra), were at the mercy of civil unrest when Emperor Augustus intervened. Juba made the city into a typical Graeco-Roman city, complete with street grids, a theatre, an art collection, and a lighthouse similar to the one at Alexandria. It was Juba who named the city Caesarea after Augustus.
Considered to be one of the more loyal provinces, Caesarea Mauretania began to grow under Roman rule, eventually reaching a population of over 20,000. In 44 CE during the reign of Emperor Claudius, it became the capital of the imperial province of Mauretania Caesarensis. Later, the emperor made it a colonia, Colonia Claudia Caesarea. As with many other cities throughout the empire, he and his followers further romanized the area, building monuments, enlarging the bath houses, adding an amphitheatre, and improving the aqueducts. Later, under the Severean dynasty, a new forum was added. Although it would recover, the city was sacked by Moors during a revolt in 371/372 CE. The area was finally overtaken by the Vandals in 429 CE; however, in 533 CE the city was seized by the Byzantine Emperor Justinian. Earthquakes have since ravaged many of the ancient remains.