Stone and stars

The Stones and Stars Project

This page is about my studies of the megalithic chamber structures of the Alentejo region of Portugal. Built by people of the period we now call "Neolithic", these "antas", as they are called in Portugal, consisted of a chamber, usually with seven large flat stones (called "orthostats") standing on end, and a corridor of two rows of smaller orthostats, both covered with large slabs of stone. The whole structure was then covered by a mound of earth, leaving the corridor as the only entrance.

While the original use of these mysterious structures is not known, I think they were probably temples for the worship of a deity, possibly a goddess associated with the star cluster now called the Pleiades.

In November 2001 I spent two weeks in the Alentejo locating and measuring 61 antas. Preliminary analysis shows that a very large percentage seem to have been aligned to a direction, or "azimuth", of between 100 and 110 degrees, measured Eastward from North. The Pleiades were rising at 110 degrees beginning about 7300 years ago and their rising point was at 100 degrees about 1500 years later. This shift is caused by Precession of the Equinoxes. Perhaps coincidentally, there are seven stars in the Pleiades cluster that can be seen in a clear dark sky, matching the seven orthostats of the anta chambers.

The sites for these structures were consistently chosen for their clear view of the horizon in the alignment direction. Only in two cases do hills rise to a height of as much as three degrees above horizontal in the alignment direction. Because the atmosphere would prevent stars like the Pleiades from becoming visible until they are about 6 degrees above the horizon, even these hills would not obstruct the view of the stars.

The association with the Pleiades is intriguing. Many sources cite the Pleiades as a sacred grouping of stars which figured prominently in the spiritual lives of many cultures, including ancient ones. Because it is the only such cluster in which the brightest individual stars can be seen with the unaided eye, and perhaps also because of its association with the very ancient constellation of Taurus,the Bull, this group of stars would have been very likely to be considered special.

What is the real meaning behind the ancient urge to build using huge stones? To build and continue the use of these monuments requires a commitment that must extend over a long time and be communicated to future generations, so that the work can be carried on. It is this shared commitment that imbues these structures with meaning and magic, and causes them to speak to us across the ages in a language all can understand, even thousands of years after their creation and the passing of their creators. Though the continuity of ceremonial intent lasted for generations, we now can only guess at their original purpose and use, based on study of the remains of the megaliths.

One obstacle to understanding the purpose of the antas is a lack of clearness about their actual age. Artifact associations have dated them to about 3000BC, but it is not known whether the artifacts were contemporary with construction or were placed long after the antas were built.

If their use was connected with the stars, and the particular stars could be identified, dating of the construction could be based on star positions and precession. However, it is necessary to verify the ages of a sample of the antas by other means to ensure that the star/precession method is correct.

A new dating method, optically stimulated luminesence, could resolve this question. This method can determine how long it has been since a soil sample was last exposed to daylight. Because the soil fill around the antas was placed by hand, it would have been exposed to sunlight then. If samples could be obtained from fill undisturbed since placement, they could yield a construction date accurate to about 5% of the true age.

An effort is under way to obtain permission and funds to enable an investigation of the ages of the antas using optically stimulated luminesence.


The Anta de Herdade da Anta has a well-preserved corridor.

This large anta at Paco das Vinhas is typical of the better-preserved ones with a good corridor.

The Anta da Bota is typical in size and condition.

About 7000 years ago in South-central Portugal, people began building massive stone structures. Their purpose is not known to us now, but hundreds of them were erected during the next 3000 or so years. These "megaliths" pose a powerful mystery, the solution to which could tell us much about the builders and their beliefs.


The Neolithic people who lived where Portugal is now were possibly the first in Europe to build the huge stone structures that dot the landscape there. The so-called "Cromelech dos Almendres" is a ring of 95 large standing stones, some more than 8 feet tall, that predates Stonehenge by more than 1000 years!