The Nuraghe Arrubiu is a monument with a complex plan of the type known as pentalobate. This means that five towers (C-G) were built around the central tower (A; preserved height roughly 14 metres); they are joined to each other by straight lengths of imposing curtain wall that enclose an irregular five-sided courtyard (B) in the centre of the monument. The central pentalobate complex is ringed by another wall, the so-called antemurale, which has seven more towers (H-P); a second set of four towers (Q-T) has been identified along the south side, with stretches of wall between them, and seems almost to be a second antemurale designed to reinforce the first.
There are three huts to the West of the complex: two of them are round, and the central one is square.
The Nuraghe was abandoned, perhaps as the result of a collapse, between the end of the Bronze Age and the beginning of the Iron Age (10th-9th centuries BC). It was subsequently occupied in the Roman period, without a break from the 2nd century BC to the 5th century AD. An installation for the production of wine ("Wine-making plant" No. 1) was established on top of the rubble in the central courtyard, and a second identical installation ("Wine-making plant" No. 2) was set up in courtyard K on the West side, in front of the entrance to the pentalobate complex. Both have been excavated, removed and rebuilt outside the complex, along the perimeter of the recently enclosed area.


THE CENTRAL COURTYARD (B)

In shape, the Central Courtyard is a large and irregular polygon of which the major axes are 9.90 metres (East-West) and 6.80 metres (North-South). The Central Tower is situated opposite the entrance passage (with a recess on the left-hand side) that passes through the antemurale. On the right is the entrance to the monumental enclosed staircase, leading to the top of the bastion; next comes the entrance to Tower E, and to the passage that communicates with Tower F. On the left is the entrance to Tower D, then a shallow recess in the surface of the wall, and finally the passage to Tower C. Around the perimeter runs a low ledge, made both of irregular stones and of squared-off blocks; a large area of ash was found on the left, resting on a layer of medium-sized stones -- perhaps a hearth.
The courtyard was completely filled with rubble. In Roman times, an installation for the production of wine was established on top of this, at a height of about 9 metres; after being completely excavated, this feature was dismantled and rebuilt outside the main complex.
One of the most notable results of the excavation was the discovery that an artificial channel crosses the courtyard. 1.5 metres deep, and ranging from 25 cm to 60 cm in width, it had been made by enlarging and deepening the natural grooves in the basalt; its purpose was to ensure that surplus water was drained away. In the right-hand part of the courtyard, a "well" was constructed on this channel, partly of worked and partly of unworked stones; it in fact works as a tank, designed to collect the water drained in the channel and thus prevent the flooding of the courtyard. This interesting hydraulic device is as old as the construction of the pentalobate bastion itself, which can be dated to the end of the 14th century BC. 

 
TOWER C

On the left-hand side of the courtyard will be found the entrance passage to Tower C of the pentalobate bastion: it is an imposing structure, built of huge blocks accurately assembled.
Inside, Tower C is circular in plan with two large square recesses on the right and on the left of the entrance. The masonry between them is perforated by ten slits obtained by setting the colossal worked blocks vertically. Of these, the first four counting from the left are stopped up with an efficient and perfectly preserved mixture of small stones, clayey earth and pebbles. The upper part of the tower is closed by a false dome, and only the top has collapsed; the internal preserved height is around 6 metres. There is a paved area, roughly 3 metres by 1 metre, in front of the slits; its function is not clear. 

 

 

THE CENTRAL TOWER (A)

The structure of the Central Tower seems to be on a smaller scale, and more regular in its general development, than the pentalobate bastion and its towers. Both the entrance passage (3.40 metres long and about 1 metre wide, with a paved recess on the right-hand side) and especially the chamber show signs of having received a severe shock, or contortion, which broke nearly all the stones and brought down the facing of clayey earth and other filling material. In spite of this, the false dome (tholos) is intact; it is almost 11 metres high and roughly 5 metres wide. There is a recess on each side of the entrance, and a third one facing it; the one on the left has an angled structure within the actual masonry.
The excavation of the Cental Tower has provided evidence for a great many details of building technique. The natural rock was first exposed: man-made cavities show where building-blocks were cut out on the spot. The uneven surface was then levelled by the addition of a layer of stones, topped by well-beaten clayey earth. This became the surface on which life was lived: many fires were lit, and they have left traces of terracotta, ash and carbon. Pots of various sizes also accumulated -- especially large containers for agricultural produce. An extensive hearth, with a vast mass of ash, grew up between the central recess and the one on the right of the entrance; it eventually spread from the wall to the centre of the chamber.
At some stage, probably for ritual purposes, a hole was dug in the exact centre of the chamber. Into this was inserted a vase, which had been deliberately perforated -- perhaps to allow liquid inside to leak out into the soil and thus propitiate the divine powers. Shortly afterwards, the chamber and the whole complex were abandoned, and sealed by the huge pile of rubble that had once been the upper storeys and battlements of the bastion and its towers.
The construction of the Central Tower, achieved at the same time as that of the pentalobate bastion, is dated to the end of the 14th century BC; it was abandoned between the end of the Bronze Age and the beginning of the Iron Age (10th-9th centuries BC).

All the ancient models of complex nuraghi show that the Central Tower would have been much higher than the pentalobate bastion; an original height of the order of 27 metres has been estimated. The maximum preserved height is 14 metres. Part of the first-floor chamber survives (internal diameter 4 metres); there must have been a second-floor chamber above it, and a balcony above that. There is a small domed cavity in the wall, about 8 metres from the ground; it seems to have been intended to lighten the massive wall of the Tower at the point of its greatest thickness. 

 
HUT 1

Hut 1 is situated opposite the West side of the antemurale of the nuraghe. It is very large (10 metres in diameter) and its wall is between 1,75 and 1,10 metres thick. Position and dimensions combine to suggest that the original function of this hut must have been an important one: as in the case of similar structures in other nuragic villages, it was probably used by the local community as a Meeting Hall. However, the hut was extensively re-used for other purposes in the Late Roman and Early Medieval periods, so that nothing now remains of the earliest arrangements except the basic outline and a few blocks along the wall (perhaps part of a circular bench). To the second phase belongs a raised ledge, made up of rounded pieces of basalt, slates and large reversed roof tiles, both intact and broken (to fit the irregular stones). The surface of one of the tiles is decorated with lengthwise wavy lines. There is an area of baked clay on the left; it is probably the remains of a hearth. Pieces of other roof-tiles were found in the same part of the hut, and so too were sherds from a number of vases, a loom-weight and a small hoard of Early Vandal coins of the 5th century AD.

 

HUT 3 

This is an irregular square structure, 10.50 x 10.75 metres, with the entrance towards the antemurale of the nuraghe. Inside, the hut is divided by two short cross walls and by a longer wall which defines a long narrow room (10.75 x 1.10 metres). The plan is difficult to read, because the walls are not connected, and because they are made of differently sized stones -- including squared-off nuragic blocks: for example, the architectural fragments used as benches along both the inside and outside of the wall to the right of the entrance (where an Early Christian clay lamp was placed). A hearth-stone, roughly 85 cm in diameter, was found on the bedrock in the North West corner of the hut. It has been re-buried for safety, until the excavation can be completed and restoration of the whole building can be carried out. In its present form, Hut 3 is Late Roman in date.


Further away, to the North, may be seen the outline of HUT 2 (diameter roughly 8 metres, wall not much more than 1 metre thick). There is no doubt that this was originally nuragic: but nothing more has survived. 

 

 
OPERATIONS

1981 Autumn I Removal of surface vegetation; laying out of general grid; survey; preparation of area for excavation. Enclosure of area begun.
Lit. 80,000,000 - XIII Comunit… Montana.
1982 Autumn II Excavation begun in courtyard B, courtyard K, courtyard X, courtyard Y. Enclosure of area
continued.
Lit. 120,000,000 - XIII Comunit… Montana.
1983 Spring -- Access road built.
Comune di Orroli.
1983 Summer III Excavation continued in courtyard X and courtyard Y with silos. Excavation of Tower P and Tower I begun. Enclosure of area completed; excavation office constructed.
(Funds remaining from Campaign II)
1984 Summer IV Excavation continued in courtyard X and courtyard Y. Courtyard B: excavation and removal of Roman level, and reconstruction elsewhere within the enclosure.
Lit. 100,000,000 - XIII Comunit… Montana.
1985 Autumn V Excavation continued in courtyard X and courtyard Y with hut.
Lit. 100,000,000 - XIII Comunit… Montana.
1986 -
1987 Summer VI Courtyard K: excavation and removal of Roman level, and reconstruction elsewhere within the enclosure; construction of two protective shelters. Courtyard B: removal of rubble begun.
(Funds remaining from Campaign V)
Lit. 1000,000,000 - Credito Industriale Sardo.
1988 Autumn -- Computerized photogrammetric aerial survey.
Lit. 200.000.000 - Ministero Beni Culturali ed Ambientali.
1989 Summer VII Excavation in courtyard K and courtyard B. Excavation of Central Tower begun. Excavation continued in courtyard X.
Lit. 100,000,000 - Credito Industriale Sardo.
-Basic software prepared for computerized inventory of worked blocks; computerized reconstruction of the monument.
(Funds remaining from 1988 - Ministero Beni Culturali ed Ambientali)
1990 - First campaign of pottery restoration.
Lit. 100,000,000 - Ministero Beni Culturali ed Ambientali.
1990 Autumn VIII Hut 1 and Hut 2. Excavation of Central Tower begun.
Lit. 1000,000,000 - Ministero Beni Culturali ed Ambientali.
1991 Summer IX Excavation of Hut 1 completed. Excavation of Hut 3. Excavation continued in Central Courtyard and Central Tower. Filming begun.
(Funds remaining from Campaign VIII)
1991 Autumn X Excavation in Central Courtyard completed, with reconstruction of drainage system. Excavation of Central Tower completed, including the first-floor chamber. Excavation of Tower C. Filming completed. Panels.
Lit. 150,000,000 - XIII Comunità Montana.


"WINE-MAKING PLANT" No. 1

During the second season of excavations (1982), the remains of a Roman structure were revealed, above the rubble that had almost completely filled the Central Courtyard (B) and underneath a layer (50-100 cm thick) of recently collapsed material.
From the 2nd century BC onwards, the surface of the ruins was adapted for use, presumably by the local Romanized population. A layer of clay was spread over the rubble, beaten down, and then paved with slabs of schist. The area was further defined by a containing wall on the North side, extending from the Central Tower (A) to the inner face of the courtyard wall. Another wall, of which only a short section remains, tangential to the Central Tower (A), probably divided the structure in two, or served as the support for a thatched roof.
This structure was used for processing agricultural produce until at least the 5th century AD. A rectangular limestone basin, with a large pouring channel, overlies another smaller and partly sunken receptacle, and was probably used for crushing grapes. Next to this is the counterweight and base, in basalt, of the press; and a number of stone bowls of various shapes and sizes. In a corner, between the dividing wall and the side of the tower, a roughly circular slab was found; it served as the base for a hearth. The ceramic material encountered during the excavation -- amphoras for transporting wine, spouted pouring jugs, glass drinking vessels -- provides further evidence of the various processes that are part of wine-making.
After being fully excavated, the whole structure was carefully drawn and photographed, and then dismantled, removed and re-assembled outside the complex, along the perimeter of the recently enclosed area: the archaeological investigation could thus proceed to earlier periods.

"WINE-MAKING PLANT" No. 2

In 1982, the presence of a Roman structure was detected above the rubble in courtyard K, in front of the entrance to the pentalobate bastion and between towers D and E. Approximately square in plan, its paved floor is almost level with the architrave over the entrance to the bastion, the outer face of which partly defines its North side. As in the similar structure revealed above the rubble in the Central Courtyard, the floor is made of beaten clay and schist slabs.
Here too, the finds point clearly to the agricultural activities of the local Romanized community, who transformed parts of the nuragic complex into a kind of villa rustica between the 2nd century BC and the 5th century AD. Traces of the associated rectangular houses can be seen around the monument: they await excavation (which is planned). As in "Wine-making Plant" No. 1, there are two superimposed sandstone basins for crushing grapes and collecting the new wine, the bases and counterweights of the press, and bowls of various shapes and sizes. There are also some small basalt grindstones, and perforated stones, which had probably been incorporated in the masonry and used to tie up the halters of the working animals. The ceramic finds encountered during the excavations -- amphoras for transporting wine, spouted pouring vessels, lamps -- show that other agricultural activities were carried out here in addition to wine-making. 
Since it was necessary to continue with the archaeological investigation of the earlier periods, this structure too was carefully drawn and photographed, and then dismantled, removed and re-assembled next to "Wine-making plant" No. 1, along the perimeter of the recently enclosed area.

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