The Aqueduct, which provided an abundant supply of water, was built in the Herodian period; it was later repaired and enlarged to a double channel when the city grew. The upper aqueduct begins at the springs located some nine kilometers northeast of Caesarea, at the foot of Mt. Carmel. It was constructed with considerable engineering know-how, ensuring the flow of water, by gravity, from the springs to the city. In some portions, the aqueduct was supported by rows of arches, then it crossed the kurkar ridge along the coast via a tunnel. Entering the city from the north, the water flowed through a network of pipes to collecting pools and fountains throughout the city. Many inscriptions in the aqueduct ascribe responsibility for its maintenance to the Second and Tenth Legions.
During this period, Caesarea became an important Christian center. The Church Father Origen founded a Christian academy in the city, which included a library of 30,000 manuscripts. At the beginning of the 4th century, the theologian Eusebius, who served as Bishop of Caesarea, composed here his monumental Historia Ecclesiastica on the beginnings of Christianity and the Onomasticon, a comprehensive geographical-historical study of the Holy Land.
Byzantine Caesarea was surrounded by a 2.5 km. long wall, which protected the residential quarters built outside the Roman city. It had a 3 m.-wide city gate in its southern section. Side by side with the Christian population and its numerous churches, there were Jewish and Samaritan communities that built elaborate synagogues. During this period, the Roman inner harbor was blocked and buildings were constructed on what had become dry land. A row of vaults serving as shops was built against the podium wall facing the port.
The main church was the Martyrion of the Holy Procopius, built in the 6th century upon the remains of the Roman temple on the podium. The octagonal, 39 m.-wide church stood within a square precinct measuring 50 x 50 m., surrounded by rooms along its walls. The floor was paved with marble slabs in a variety of patterns. Of the rows of columns in the building, several Corinthian capitals decorated with crosses were found.
A very large and elaborate building, which included numerous courtyards and rooms spread over the area of an entire insula (block of buildings) and surrounded by the main streets of the city, was dubbed the government building. Its entrance was from the cardo (north-south main street), its western side supported by a row of vaults, which had once served as port warehouses. One such vault facing the decumanus (east-west main street) was plastered and decorated with red and black wall paintings, including depictions of Jesus and the twelve apostles.
A large hall with an apse, located in the center of the government building, served as the hall of justice. Fragments of a Greek inscription found here refer to an imperial decree dealing with fees that clerks of the court may collect for services rendered. In the northeastern part of the building was a group of rooms with mosaic floors; one with a quote from Pauls Letter to the Romans. (13:3) Rectangular niches in the walls of a long hall north of the hall of justice probably served as an archive.
Remains of a 5th century synagogue were found on the seashore north of the harbor. The rectangular building faces south towards Jerusalem. Architectural details were found in its ruins, including capitals with carved menorot (candelabra), a column inscribed shalom and parts of a Hebrew inscription listing the twenty-four priestly courses in the Temple in Jerusalem.
Remains of several other large buildings were exposed, among them an elaborate 4th century renovated bathhouse. It consisted of groups of courtyards and rooms with benches along the walls, most of them paved with mosaics, and in the caldarium (hot-room) area were several rooms with a heating system (hypocaust). Some particularly elegant rooms were paved in marble and had mosaic decorations on the walls; one depicts a female with the words "pretty woman" next to it.
Inside the amphitheater, which was no longer in use, a two-level palace was built with a staircase connecting the two levels. The upper level included two courtyards and rooms paved in colored tiles or mosaics and served as the residence. The lower level had a courtyard with an apse on one side, paved in colored tiles. Along this courtyard stood two rows of columns with a marble chancel screen between them and in the northern wall was a fountain with a rectangular basin below it. This lower level served as an open garden.
In 639, Caesarea was conquered by the Arabs and its importance, as well as its population, dwindled. Urban areas were abaand replaced by agricultural terraces. This Arab town was surrounded in the 10th century by a 3 m.-thick wall, remains of which were found during the excavations.
Caesarea of the Crusaders