Obelisks

The word obelisk is taken directly from Greek, where it is a diminutive of the word obelos, meaning a spit or similar pointed object. It was used by the Greeks to refer to a characteristic monument of ancient Egypt, a tapered stone shaft with a pyramidal top, typically erected in pairs on the two sides of the ceremonial way approaching the entrance of a temple. They were called benben or tekhennu in Egyptian. They were usually erected by a Pharaoh to mark the celebration of his jubilee, when he had ruled thirty years (the canonical fifty was too long, apparently, and some could not even wait thirty). The true Egyptian obelisk was made from a single block of red granite or similar rock, and its pyramidal top, the pyramidion, was sheathed in gold or electrum, and was about a tenth of the total height. It was an offering to the sun god Re, whose rays glistened at its top. There was a small chamfer at each corner of the base. The cross section was often square, but could also be rectangular. In the latter case, the pyramidal top did not come to a point, but to a line. The lateral surfaces were covered with hieroglyphs expressing prayers and boasts of the Pharaoh. Pyramids were actually short obelisks, just the caps, and had similar religious meanings. Pyramidion is just pyramid with the Greek diminutive ending -ion.

The stone for Egyptian obelisks often came from the igneous rock quarries at Elephantine, opposite Syene at the first cataract. These resistant rocks are, in fact, the reason for the cataract, which is not a waterfall, but the confused rocky rapids where the Nile penetrates this hard barrier. This rock is called red granite by nongeological authors, but the area gave its name to syenite, a granite-like rock deficient in quartz. The rock is actually a granodiorite, since it is not all that deficient in quartz. This rock is very durable, and takes a high polish. The obelisk was roughed out at the quarry, and shipped down the Nile to the point closest to its intended site. All sites in Egypt are close to the Nile. It was dragged out by men on ropes, it and probably they sliding on mud. It was finished and lettered in place, then laboriously erected by levering it up and building a mound of earth under it, until it could finally be pulled upright. When Augustus moved obelisks 1500 years later, he had pulleys and cranes and wheels, which the early Egyptians did not have. What would have been the tallest obelisk still lies half-quarried in Elephantine, abandoned when a fissure was discovered. The obelisk at Edinburgh, seen at the left, is made of ashlar, not a single piece of stone.

Queen Hatshepsut of the Eighteenth Dynasty erected some six obelisks in the 16th year of her reign, around 1485 BC. One still stands at Karnak, 97.5 ft high, 8.6 ft wide at the base, and 5.3 ft wide at the top, making a taper of 1 in 27. The width measurements were scaled from a photograph. This was the tallest obelisk ever erected in her day. Some later obelisks were taller, but 100 ft is a good representative height for a major obelisk. Thutmose III, her great contemporary, erected two obelisks at the temple of Re in Heliopolis a few years later. Thrown down by the Persians, these two were moved to Alexandria by Augustus a millennium and a half later to decorate the palace built by Cleopatra, and then in the 19th century one went to London, where it stands on the Victoria Embankment by the Thames (1878), as shown in the photograph, with pigeon guano instead of gold on its pyramidion, and the other went to New York, where it stands in Central Park (1881). These are 69.5 ft high, with bases 7.75 ft wide, and are called Cleopatra's Needles. An obelisk from Luxor was brought to the Place de la Concorde in Paris (1836), the first brought to Europe in modern times. The foul atmospheres of these northern sites have severely damaged them. Constantius brought two obelisks of Thutmose III down the Nile in 351 from Karnak. One, called the Lateran obelisk, wound up at the Circus Maximus in Rome. The other was moved to the Hippodrome in Constantinople by Theodosius in 390 after many years at an Egyptian port. The Lateran obelisk is gone, but the Theodosian obelisk still stands in Istanbul, somewhat shortened to 60.7 ft from its original height of 98 ft due to accidents.

Augustus also brought two obelisks to Rome. One was erected in the Circus Maximus, and the other in the Campus Martius as a large sundial, the Solarium or Horologium, in 10 BC. The first mentioned was a porphyry obelisk of Psamtik I, 75 feet high. Gaius (Caligula) erected the obelisk from Thebes begun by Thutmose III and finished by Thutmose IV in the Circus Vaticanus, to mark the turning point of a racetrack, a popular use. This 105.5 ft shaft ended up in front of St. Peter's in Rome. It was still standing, the last one in Rome, and was moved to its current location in 1586. Most of the obelisks erected in classical times in Rome were recovered and now stand again. How this was done is told by Peter Tompkins in The Magic of Obelisks (New York: Harper and Row, 1981). If you are interested in obelisks, you will be fascinated by this book. The latter part of the book is devoted to the superstitious nonsense about Egyptian mysteries that is still popular. The facilities available in 1586 were essentially those available to Augustus, and Tompkins gives some idea of the magnitude of the work. Tompkins goes on to describe the history of obelisks since then, and their connection with hieroglyphs, Rosicrucians, Masons, and religious barbarism in general. Most obelisks were overthrown by Persians, Christians, and Turks, just as most royal Egyptian tombs were robbed in the Renaissance to supply popes, cardinals, and bishops.

In 2008, a shaft called the Axum obelisk was re-erected in Ethiopia. It was taken to Rome by the Italian army that invaded Ethiopia in the 1930's, but was returned in three parts in 2005. It stood in front of the African Colonial Offices in Rome. This is more accurately called a stele, since it was of rectangular cross-section and at the top was a semicircular crest, not a pyramidion. It was made in the 4th century of granite, and is 79 ft high. A similar stele, marking the tomb of King Ezana, remained in Ethiopia and is now joined by its twin. There is no inscription on it, as on an Egyptian obelisk, but the representation of doors on the ground floor and windows above. An attempt was made to construct a 108 ft high stele, but this was too ambitious, and it lies fallen in the same area.

The Washington Monument, built 1848-1884, has the shape of an obelisk, but is, of course, not monolithic. The Egyptians would approve of its giant size, 555 ft 5-1/8 in high. A similar but much smaller and more graceful Washington Monument stands in Baltimore, and a still smaller over Washington's grave at Mount Vernon. All these monuments have Masonic connections. The Bunker Hill memorial in Boston, designed in 1825 by Horatio Greenough, who said it says Here!, also has the shape of an obelisk. In fact, the obelisk form has retained its popularity as a monument for nearly 4000 years so far. The Ames monument in the Sherman Mountains between Cheyenne and Laramie is a pyramidal obelisk made from the local red granite. At the right is an obelisk used as a war memorial in Plymouth, England. An impressive obelisk commemorates Sgt. Floyd of the Lewis and Clark expedition in Sioux City, Iowa. He was the only fatality of the Corps of Discovery, victim of a burst appendix.

An obelisk makes a fine outdoors gnomon, that can be used as a sundial or calendar, as was done by Augustus in Rome. The end of the shadow can be marked for certain important times, as well. On Augustus's birthday, the shadow of the Solarium pointed to the Altar of Peace. From the shadow of an obelisk, the compass directions can be accurately determined by standard observations, as well as the latitude of the place.

To find the volume of an obelisk, it is divided into the shaft and the pyramidal termination. If the base is a rectangle a by b, and the top a rectangle of a₁ by b₁, and its height is h, then the volume is given by the formula:

The formula is a little simpler if the obelisk is square, and works for the pyramidal termination as well as for the shaft.

Finally, Obélix was Astérix le Gaulois's large companion in the cartoon books by Goscinny, popular in France in the 1970's, and his day job was transporting menhirs, parts of monuments that have nothing at all to do with Gauls or obelisks. Oil well drilling derricks of the 1920's and 1930's had the shape, in wood or steel framework, of an obelisk, with a walkway around the termination. You can probably fill in other examples from your own experience.

Composed by J. B. Calvert
Created 16 September 1999
Last revised 5 September 2008