Caesarea

The concrete that made Sebastos possible was also its weakness. When ROMACONS tested the Caesarea cores, all five came out substantially weaker than the Italian cores the project had sampled, two of them at less than half the compressive strength of its benchmark block from Santa Liberata. Lumps of lime never properly worked into the mortar show up in all five, more often than at the Italian sites, and the team's impression was that the mortar did not bond to the local kurkar rubble as well as it does to Italian tuff.

Geology did the rest. The harbour was built beside a fault running close offshore, and seismic movement tilted the moles and let them settle into the seabed; seabed deposits record a tsunami striking at some point in the first or second century CE. Researchers still differ over how much weight to give each cause.

The outcome is clear enough. By the sixth century the harbour was unusable, and the jetties now lie more than five metres down. The city carried on (capital of Palaestina Prima from 390, and a centre of Christian scholarship where Origen wrote and the school of Caesarea kept a library reported to hold more than 30,000 manuscripts) but the engineering marvel that justified it had gone under.

The theatre is the first thing most visitors meet. It is Herodian in origin, semicircular, and holds about 4,000 seats in its present form; the Caesarea Development Corporation calls it one of the largest and finest found in the country. At the end of the Byzantine period the orchestra, the flat performing floor, was turned into a pool for water displays. It is a working music venue again, and playing it is treated by Israeli performers as a career marker.

South of the harbour, Josephus records that Herod built an amphitheatre 'capable of holding a vast number of men, and conveniently situated for a prospect to the sea'. The long, narrow arena beside the promontory palace is that building: a course for races and games rather than a Roman amphitheatre in the later sense, and the sea forms one whole side of it. Herod instituted games every fifth year in Augustus's honour and, Josephus says in the Jewish War, first offered the largest prizes at them in the 192nd Olympiad.

The far larger circus lies east of the built-up city. The Caesarea Development Corporation dates it to Hadrian's day, on the model of the Circus Maximus, covering some 31,500 square metres and in use into the sixth century. Its kurkar seating was robbed out long ago, but the vaults that carried the tiers survive, along with the spina: the central barrier, fitted with pools and crowned by an obelisk of Aswan granite.

Between them the three make the point. A city with a theatre, a seaside racing arena and a circus was not a provincial afterthought; it was a Roman capital.

The most photographed thing at Caesarea is not in the ticketed park at all. The high-level aqueduct runs north along the sand on a line of arches, half-buried in dune, and the beach beside it is listed by the Caesarea Development Corporation among the town's bathing and water-activity sites.

The water came from the foothills of the Carmel to the north-east, and the channel crossed two valleys, Nahal Tanninim and Nahal 'Ada, on its way in. How far off the source was depends on the channel: 'En Shuni, which fed the first two, lies about 7.5 km north-east, while Britannica puts the springs almost ten miles (16 km) away. What looks like one aqueduct is several channels built against each other over centuries: Channel A first, then Channel B alongside it (both fed from 'En Shuni), then Channel C replacing B and tapping the higher springs of Nahal Tanninim.

The dating comes from five salvage excavations between 1994 and 2002, published by Yosef Porath and others. Channel A went in between Herod's inauguration of the city in 10/9 BCE and the reign of Hadrian; the architecture and plaster suggest it came after Herod's own time, probably under the Flavians, and Channel B is Hadrianic. The system stayed in use for roughly six centuries, until the city fell in 640/1.

Later Caesarea needed more: a low-level aqueduct from the reservoir behind the Nahal Tanninim dam, and a ceramic pipeline from a spring about four kilometres south-south-east. The low aqueduct's date is disputed: Yeshu Dray puts it at the end of the fifth century or the start of the sixth, on the strength of a letter from Bishop Procopius of Gaza to the emperor Anastasius I, against Porath's 2002 estimate of the late fourth or early fifth. By the Crusader period the shrunken town made do with an open canal.

Baldwin I took Caesarea in 1101, in the wake of the First Crusade. He demanded surrender, was refused, and began a siege on 2 May with trebuchets; the city fell after fifteen days of resistance, whereupon part of the male population was killed, women and children enslaved and the place looted. Among the spoils, William of Tyre records, was a vessel 'of the most green colour' that the Genoese took as their share and thought to be emerald: the Sacro Catino in Genoa, identified as the Holy Grail only in the thirteenth century, and in fact glass.

Saladin retook the city in 1187, the Crusaders again in 1191. Then, in 1251, Louis IX of France refortified it. His walls and dry moat are what you walk in through: a circuit enclosing about 120 dunams, a fraction of the Roman city, defended by fifteen towers with arrow slits, pierced by three gates, and fronted by a slope down into the ditch. The Caesarea Development Corporation puts the wall promenade at about 1,500 metres. The eastern gate, restored in the 1960s with its own fallen stones, has cross-vaults that catch the moment Romanesque turns Gothic.

It did not save the town. In 1265 the Mamluk sultan Baibars had his troops scale the walls in several places at once and then demolished the place deliberately, as he did the other Crusader ports, so it could not be used again. The decline had begun earlier: Benjamin of Tudela, in the twelfth century, counted only 200 Jews and 200 Samaritans here.

The last inhabited chapter is recent, and short. In 1880 the village of Qisarya was allocated to Bosniak refugees who had left Bosnia after the Austro-Hungarian occupation of 1878; fifty families, mostly from Mostar, built a town out of ancient masonry, with two mosques, a caravanserai and a market. It did not survive the 1948 war: the standard account, following the historian Benny Morris, is that part of the population left in February 1948 after a bus attack by the Lehi militia and the rest were expelled by the Palmach, which then demolished the houses. One mosque still stands beside the harbour.