blocks were used in its construction. The roughly oval-shaped structure encloses an area 262 feet by 180 feet and contains a number of stone features, including the Conical Tower.
The Great Enclosure evolved to its final state over the period of time during which Great Zimbabwe was a large town. Two high walls form the narrow parallel passage, 180 feet long, that allows direct access from the north entrance of the enclosure to the Conical Tower.
The inner wall of this passage was originally built as the perimeter wall; the massive outer wall was constructed later, surmounted by monoliths and decorated with two courses of chevron pattern high up on the external face in the area of the Conical Tower.
The Conical Tower, one of the last structures to be built in the Great Enclosure, is 33 feet high and 16 feet in diameter at the base, tapering to 6.5 feet at the top where, originally, there were an additional three courses of 'dentelle' decoration. It is solid, built of granite blocks throughout, and rests directly on the ground with no underlying chamber.
Its large size and seclusion behind an equally massive enclosure wall, together with the narrow passageway leading to it, indicate that it was an important structure. Next to it is a smaller tower, and similar examples are also found in other Valley Enclosures.
The purpose of the towers is unknown but as they seem to have had no functional use they were probably symbolic. Traditionally, the Conical Tower is said to represent a grain bin, symbolising good harvests and prosperity. The remains of stepped platforms and hut floors are found inside the Great Enclosure but most of the archaeological stratigraphy which would help explain its function and history was removed between 1890 and 1910.
It has been suggested that it was the chief's residence or a court for the chief's wives or a premarital initiation school.
It has been estimated that there were about 50 households within these stone wall enclosures.
The archaeological evidence suggests that these were the homes of the more important people, while most of the population lived in huts set close together on the periphery of the enclosures. The population for the whole of Great Zimbabwe during its heyday is estimated at between 10 000 and 18 000. Within the Valley Enclosures are the remains of dhaka huts, platforms and small towers.
The seventh Zimbabwe Bird, now used as the National Emblem, was found in one of these Enclosures; in another enclosure a large hoard of iron and copper objects, beads and pottery was found. Many of these enclosure walls are built in the later style of walling, suggesting that the town layout in the valley changed with time, possibly to accommodate an increasing population.
Dating and origins
Despite several attempts by people to argue for an early external origin for Great Zimbabwe, no professional archaeologist has ever suggested anything except a local Shona origin for this site. In 1906 the archaeologist Randall MacIver suggested that it was of a relatively recent date and not of foreign origin.
This opinion was unpopular with most of the local white community and gave rise to heated debate, whereupon Gertrude Caton-Thompson was requested to investigate the site. By 1932, after detailed excavation, she showed conclusively that Great Zimbabwe was of African origin and less than 1 000 years old.
Her archaeological evidence was obtained from different areas within the site and was based on two criteria. Firstly, most artifacts were unquestionably of local production, while the few imported objects could be easily dated. Celedon pottery from early in the period of the Chinese Ming Dynasty (1384-1644) is one of the most frequent imports found at Great Zimbabwe.
Secondly, she excavated to natural soil or bedrock in all her areas and was thus able to obtain a complete stratigraphic sequence of material. At every level she found the remains of what had been an African way of life. These conclusions have been confirmed by the work of subsequent archaeologists.
Since the 1960s radiocarbon analysis has 