What is so beautiful about this door? (Cast brass door for the Artuqid Palace in Diyarbakir)

Introduction

The sixth and final category in the book contains five dissimilar designs. The first and most grand of all is the Artuqids Palace door in Diyarbakir, Eastern Anatolia. Al-Jazari opens this chapter with some enthusiastic message very unusual for him:

It is the masterpiece; to view it saddles are strapped on. Truly it is the pearl, the orphan, a priceless possession.”

This passionate text surprised me because this door, engineering speaking, is quite simple and doesn’t contain the inventions and surprises included in most of al-Jazari works. The beauty is not in engineering, but in the art and the craft. Donald Hill, translator, and interpreter of the book, Engineer by heart, was interested mainly in the casting technology: “Of particular importance, also, is the first unequivocal description of metal casting in closed mould-boxes with green sand, a method not used in the West until the end of the fifteenth century.” Casting is a manufacturing process in which a liquid metal (al-Jazari used copper, brass, and bronze) is poured into a mold with the desired shape. “Green” sand is used even today. The name is a bit confusing as the sand is not green color at all. Instead, the sand is called “green” because it is “wet” sand, which contains water and organic bonding compounds much like we say “green wood” in carpentry.

I have two very different questions:

  • Sorry, what is so beautiful about this door? Or at least why al-Jazari admired his work?
  • How is it possible that military considerations are not part of the design? What does it say about al-Jazari as an engineer?

Description of the door and its beauty

It is a door with two leaves which rise to the height of about four and a half meters (originally 18 spans ( شِبْر) ) and the width of each leave is a meter and a half.

The Palace door, Topkapi Manuscript, 1206

The Palace door, Topkapi Manuscript, 1206

In the center of each leave, there is a complex geometric pattern that includes Hexagram (Star of David) and Octagram. It is interesting to note that both these shapes belong to the family of Magic stars. A magic star is a star polygon in which numbers are placed at each of the n vertices and n intersections, such that the four numbers on each line sum to the same magic constant: M=4n+2. The solutions I know to magic stars are only from the 20th century, but the use of the two was very common in the Muslim world. Is it possible that al-Jazari sensed mathematical beauty without knowing the math?

Since it is a relatively complicated pattern, I colored the drawing to see Magic Stars:

Islamic art makes frequent use of geometric patterns which were developed over the centuries. There is  “artistic unity” across time and place. I bring three pictures of three doors with different geographical, cultural and historical background, both Shi’ite and Sunni Islam

The left door is a Turkish door from the14th-century. The middle door is a Grand Palace in Fez in Morocco from the 13th-century. The wooden door from Iran on the right is not dated.

The Islamic aesthetic shift toward complex geometric structures is attributed to the prohibition in the Qur’an of figurative images to avoid becoming objects of worship. Geometric structures are abstract, emphasized symmetries, and suggested infinity and therefore reminding Muslims the idea of the infinite nature of Allah. This explanation does not satisfy me since the second commandment :

” Thou shalt not make unto thee any graven image or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. Thou shalt not bow down thyself to them, nor serve them”

Did not yield a similar tradition in Jewish art. I don’t see anything that would justify the special enthusiasm from the geometric patterns of al-Jazari. However, if any of my readers find some special beauty or a hidden message, please comment as I would love to learn.

The pattern was bounded by brass plates a which carried Kufic((كوفي ) inscriptions and leaf motif decorations. This reads “the dominion is God’s, the One, the Conqueror”

Kufic is the oldest calligraphic form of the various Arabic scripts. Kufic developed around the end of the 7th century in Kufa, Iraq, from which it takes its name, and other centers. Kufic was prevalent in manuscripts from the 7th to 10th centuries. In the late 12th century, when the door was made, it was less used, and I do not know if this choice has a special meaning?

The calligraphy is surrounded by  bronze plates which were decorated with red copper leaves:

The process is relatively complex; firstly, he casted bronze panels. Using a scalpel, he carved the leaf template and poured melted red copper.

In the drawing, there are no brass domes, but in the text, there is a detailed explanation and diagram of a dome. I took the liberty to add this to the original drawing by al-Jazari:

I did not cover every detail, but I cannot ignore the door’s knockers from cast brass in the shape of two connected serpents, their heads facing each other. Their mouths are open as if they wished to devour the lion between them.   The door did not survive (I am convinced it was built, and not just designed, because of the richness and the details in the text). It is interesting to note that very similar Bronze door-knockers from the Great Mosque in Cizre are now in the Museum of Turkish and Islamic Arts in Istanbul. To my surprise, pretty similar versions have found their way to Copenhagen and Berlin museums.

We will never know what caused al-Jazari to be that happy with this door. Maybe he enjoyed his geometric patterns and thought particularly beautiful, Maybe He enjoyed his success in the complex casting or his work with various metals, brass, copper, and silver, maybe he was happy the amount and richness of the details and possibly it was a combination of all.

 

Military engineers and engineering history

Engineering has existed since ancient times, the invention of a pulley, the construction of the Egyptian pyramids or the copper production process are all “Engineering” according to all modern definitions but only in the 14th century was the first use of the term engine’er. The origin of the word is from Latin words “in generare” meaning “to create” but relating to the designing or creating engines of war like the catapult or assault towers. For many years all the engineers were military engineers. Archimedes, a gifted mathematician and scientist had a major role in the Second Punic War. He improved the power and accuracy of the Catapult, He designed a giant claw to destroy Roman ships, and the peak of his inventions was burning the Roman fleet using mirrors.  Leonardo da Vinci engineering career included military chapters as evident from his letter to Ludovico Sforza, ruler of Milan. He wrote:

“I have plans for very light, strong and easily portable bridges with which to pursue and, on some occasions, flee the enemy.. Also, if one cannot, when besieging a terrain, proceed by bombardment either because of the height of the glacis or the strength of its situation and location, I have methods for destroying every fortress.”

The Faculty of engineering at the Technion is still called “civil engineering,” to be separated from military engineering, although the former has become almost a non-issue in the modern world of engineering.

It is somewhat surprising that there is no military engineering chapter al-Jazari’s work and even when he builds the door for the Palace, no considerations of strength or defense capability are mentioned, not even a single word. Two possible explanations:

  1. The principality in Diyarbakir was so peaceful that there was no need for a military engineer.
  2. The expectations from the Court engineer in Diyarbakir were different.

 

A change in Diyarbakir and al-Jazari as an “engineering magician.”

The dynasty was founded by Artuk Bey, a general under the Seljuq emir of Damascus. In 1086 he was appointed the governor of Jerusalem, a surprising twist to a story about a Muslim dynasty which ruled in Diyarbakir Anatolia. We need to remember that the Middle East map in the 11th and 12th centuries is very different from the map we know today. After Artuk death in 1091 his sons, Sökmen and Ilghazi were expelled from Jerusalem by the Fatimid vizier and set themselves up in Diyarbakır and Mardin in Anatolia.

This door was installed at the Artuqid Palace in Diyarbakir where al-Jazari was the court engineer. The Palace was built within the walls of Diyarbakir during the reign of Salih Nasreddin Mahmud (1200-1222) Artuqid king who employed al-Jazari like his father and brother before him. The Palace was excavated in the 1960s, but most of it is still buried under the mound, and I have a fantasy that the site will be excavated a second time and we will find some of the remains of al-Jazari’s work. In the 12th century, there were a few battles with the Crusaders, with Georgia and clashes of within the Muslims. I don’t think a peaceful period is the explanation of the absence of the military aspect in al-Jazari’s work.

The Artuqids are a Turkmen dynasty which started as a warrior tribe, and its original power was military. In the 12th century, they were settling in the old cities of Amida (the previous name Diyarbakir ) and Mardin. These are ancient cities with urban culture since the Assyrians. The population is diverse and includes veteran Christian and newcomer Turkmen population as well as other migrants from Iran and other places that continued through the 13th century. Beyond the monumental Al- Jazari book, there was probably a workshop for copying and illustrating manuscripts. Rachel Ward identified two other illuminated manuscripts that were produced there. There were new architectural designs, Sharon Talmor as part of her graduate work at the University of Tel Aviv found three which mark a new era in Islamic architecture. As a part of the assimilation of a warrior tribe into the urban setting, there was probably a need for a change, and there was a thirst for cultural and artistic activities. I’d love to hear other suggestions too, but this is a possible explanation for the absence of military engineering.

So the circle closes. The question of the beauty of the door is connected to the role of al-Jazari. As we step into the book, I think we will be more convinced of his role as  “a magician of engineering”  the man who harness science and technology to create and beauty and astonishment.

 

Al-Jazari Combination Lock and the Boxes from Isfahan

“This Ifrit bore me off on my bride night, and put me into a casket and set the casket in a coffer, and to the coffer he affixed seven strong padlocks of steel and deposited me on the deep bottom of the sea that raves…and this wretched Jinni wotteth not [does not know] that destiny may not be averted nor hindered. ”

The Story of King Shahryar and His Brother from The Arabian Nights, translator Sir Richard Burton,1850.

 

In Category six that consists of “dissimilar designs” al-Jazari describes “A lock for locking a chest using 12 letters of the alphabet”.

Locking board in the alphabet lock, Topkapi manuscript, 1206

Description of the Chest by al-Jazari

The technical explanation, as always, will be colored in blue, so anyone who is not interested in cylinders or cotter-tapered pins can skip those bits. This is a chest with four combination locks in the four corners of the cover. Each combination lock uses sixteen out of twenty-eight letters in the Arabic alphabet; it uses the letters without a diacritical mark, a point, or sign added to a letter to distinguish it from another similar letter. For example, the difference between bāʾ ب (comparable to b in English) and nun ن (comparable to n in English) is the location of the point below or above the letters. Al-Jazari doesn’t explain his choice, perhaps to prevent mistakes.

The four dials

Chest reconstruction from HTTP://WWW.JAZARIMACHINES.COM/EN (link is not working anymore)

 

The four dials on the chest cover are relatively complex. Each dial consists of three disks with a triangular notch in its outer perimeter. When all the notches were aligned, the chest could be opened. I attached the original drawing of al-Jazari cross-section of the dial with the modern drawing of Hill and added captions:

Integrated drawing of the lock components, the original drawing by al-Jazari, with the modern drawing by the book translator and annotator, Dr. Donald Hill

Since it still seems complicated to comprehend, I added the drawing of the components before assembly:

The dial component, a drawing by the book translator Donald Hill, with my captions

When you turn each of the three cylinders to their proper letter, all notches are aligned and allow the opening of the lock. It requires the knowledge of twelve letters, three letters per each dial multiplied by four dials. This system is held in place together but allows convenient rotation of its components using a cotter-pin. When you want to change the code, you remove the pin and mechanically rotate the disc so the location of the notch will match the chosen letter.

The Isfahan Boxes

None of the wonderful machines of al-Jazari survived the hundreds of years passed, and all we have are beautiful manuscripts. I fantasize about an extensive archaeological excavation in the Palace in Diyarbakir that would reveal remnants of the castle’s clock or any other monumental work. Until then, both boxes with alphabet locks from Isfahan in Iran dated to the late twelfth century are the closest thing to time travel, to see al-Jazari at his work. In the David Museum in Copenhagen, there is a fragmented brass box inlaid with silver and copper with four alphabet locks. The four dials are in a straight line and not in the four corners of a rectangle, but the similarity to al-Jazari’s chest is evident. Like al-Jazari each dial contains 16 letters. The letters which are used are without a diacritical mark. There is a resemblance to the locking process and the details of the mechanism. The box is simpler, and each dial has just two cylinders. Only eight letters (and not twelve) are required to open the crate. On the box there is the maker signature saying:

“Work of Mohammed b. [Ben] Hamid al Asturlabi

 Al Isfhani in the year

Five hundred and ninety-seven [1200 AD]

And I have tested it[it works]”

Fragments of a box made by Asturlabi, 1200 AD, Museum David Copenhagen

To my astonishment there in another safe from the same period by Asturlabi at the Boston art museum. This box also has four alphabet locks of two cylinders, creating eight-letter code. This time also there is an additional three guards’ façade, probably as symbolic protection from a later period. The signature indicates that the box was prepared by Asturlabi four years earlier (593 to AH or 1197 AD). Although it’s childish, I can’t help feeling a bit left out: why two boxes by Asturlabi from Isfahan have survived and not even one machine by al-Jazari? There is no answer, nor there can be one.

Box by Asturlabi,1197 AD, Isfahan, Boston Arts Museum

Astrolabe

From the name of the maker, it is obvious that his profession and probably the family profession was producing astrolabes. Astrolabe (ٱلأَسْطُرلاب) is a sophisticated device of astronomers and navigators to measure the angle of a star above the horizon. It has many functions but was used primarily for finding latitude when you know the local time or as a clock when you know your position. There is a good explanation and a demo here. Four astrolabes from the 12th century created by Asturlabi family from Isfahan still exist, but I could not find their pictures. There are pictures of astrolabes from Isfahan from the 9th century until the 16th century, and this is one beautiful example:

The 13th-century astrolabe from Isfahan, Muhammad B.AbiBaker, The Museum of the history of science, Oxford.

Surprisingly, perhaps, there is a link between the astrolabe and the combination locks. The lock consists of rotating cylinders with respect to the alphabet circle. In the astrolabe, there is a framework called “Rete” bearing a projection of the ecliptic plane and several pointers indicating the positions of the brightest stars. This frame is free to rotate in respect to the astrolabe disk, called the mater (mother). Both the astrolabe and the alphabet lock are rotating mechanical systems around the center. This is done in both cases by using a cotter pin (a tapered pin) that holds all the components in place and allows rotation around an axis. This pin has the shape of a horse head, hence his name in Arabic فرس (mare). I attach a photo of astrolabe dismantled; you can see exactly the same mechanism and the same cotter pin (red circle) as in the drawing by al-Jazari above.

Astrolabe dismantled for parts. The cotter pin in the red circle

If you really want to go on a historic-scientific journey, you can read the guide that Geoffrey Chaucer wrote for his 10-year-old son Lewis. Chaucer, one of the fathers of the English literature and the author of “The Canterbury Tales” was also an astronomer. This is the first publication in English on this topic as well as a great introduction to the Astronomy in the 14th century. The guide contains more than fourty (!) uses the astrolabe.

Who’s ahead?

Al-Jazari wrote  in the opening paragraph:

“The earlier [workers] in this craft made locks for locking and opening by means of the letters. Among them were [those that] locked by means of  four  a chest and made a lock on its lid as I shall describe”

Al-Jazari, obviously, did not claim primacy. Is it possible that the Isfahan boxes are part of the boxes that al-Jasari mentioned? Could it be that al-Jazari book got to Isfahan and inspired Asturlabi to build his boxes? The answer is probably no to both. The boxes were made in the years 1197-1200. We don’t have an exact date for completion of the book.  Rachel Ward claims that the book was written between 1200 to 1197. It’s a little earlier than Donald Hill who believed that the book was written between 1204-1206. The small gap is due to different sources. Hill was relying mainly on the copy from Oxford University, and Ward is basing her calculation on the earlier copy of Topkapi. Either way, the closeness between the time the book was written and the dates of the production of the boxes in Isfahan almost negates the possibility of mutual influence. Much more likely is both the Isfahan boxes and al-Jazari’s chest are part of the same rich material culture in the Muslim world at the time.

It is interesting to note that the first alphabet lock in Europe is probably the work of Giovanni Fontana, A Venetian engineer from the 15th century, three hundred years after al-Jazari. Fontana was very diverse, including measuring heights with falling stones, water and sand clocks, and trigonometric measurements. He wrote one of the first technology books in the Renaissance: “Bellicorum Instrumentorum Liber.” The book includes siege machines but also fantastic inventions like a bird propelled by a rocket, and an early version of four wheels bicycles and last but not least an alphabet lock:

The alphabet lock of Giovanni Fontana, 1420-1430