Sword of Islam, Sword of Ali.
Seal of the God Adad.
9th century BC
emblem developed within the islamic world is the so-called “Sword of Islam”,
also called “The Sword of Ali” or Dhu
‘l-Fakar. This sword usually is depicted as a two-pointed sword. Other
versions show the sword with two blades, usually parallel but sometimes also
making a sharp angle. Another version is a sword of a turkic shape, the blade
with one sharp curved side. This sword differs from the European sword which
has two straight sharp sides. The sword with the curved sharp side is also
called “The Sword of Islam” in islamic heraldry.
There are some good reasons to accept the idea that the Sword of Islam goes back to very old examples. On a 9th century BC seal of the god Adad a man is depicted with a sword with two blades.  This is thought to be a thunderbolt. Such a thunderbolt, consisting of a bident of two wavy points is also on monuments of Nebuchadrezzar I (1125-1104 v.C.) and Assur-nasir-pal II (883-859) together with the emblems of the territories captured by them.  After that there is a “missing link” of almost a millennium, not of the thunderbolt but of the sword in the shape of a bident.
The Sword of Islam is a prolongation of the Sassanian tradition in which the Shāhānshāh in full official dress is depicted with a sword upright between his knees. This example was followed by the first caliphs. This may be demonstrated by a silver dish from the Hermitage of St. Peterburg.  On it is a prince, probably the famous caliph Ali (656-661 AD), sitting in a Sassanian cross-legged way and with a sword upright between his knees. In other examples the sword of the caliph is two-bladed, an innovation because the Sassanian swords certainly were not.  An ancient picture of it is on early Arab-Sassanian coins showing a man, probably Muhammad himself or one of the first caliphs, armed with a two bladed sword.  On a coin of Abd el Malik (685-705) the caliph has a sword with a wavy line between the blades an this confirms the more the idea that a thunderbolt of a God is depicted.
By the same caliph however, another symbol of a thunderbolt was introduced, replacing the two-bladed sword with the wavy line. This was the (demi-) hellenistic and roman thunderbolt, usually called a fleur de lys. This emblem, supported by two lions, occurs on his seal, today in the Archeological Museum in Istanbul.
Two bladed sword on an
early Islamic coin
Probably from the time of
Ali (656-661 AD)
Two bladed sword
on a coin of Abd al Malik
In a later Islamic tradition Dhu’l-fakar is the name of
the famous sword Muhammad captured at the battle of Badr (624)  “Initially it belonged to an unbeliever called
al-‘As b. Muabbih who was killed in the battle. The sword is mentioned in the
Sira (ed. Sakka, etc. 1375/1955), ii, 100 and in several hadiths (see for
example Ibn Sa’d, ii, 2. part fi suyuf
al-Nabi). The expression Dhu ‘l
Fakar is explained by the wire edges (fukra) or furrows (cf.
the expression sayf mufakkar) on the sword. According to tradition the
sword had an inscription about retaliation that ended with teh words la yuktal Muslim bi-kafir la yuktal
Muslim bi-kafir (No Mulsim will
be killed for an unbeliever). The maxim la sayf illa Dhu’l-Fakaris is often written on beautifully engraved
swords from the middleages up the the present day in all of the Muslim world.
The words wa-la fata illa Ali are sometimes added because, although it
had been the sword of Muhammad, it afterwards had been of Ali and was
transferred to all other Abbasid caliphs, it had become the attribute of Ali
and the emblem of all followers of Ali. Islamitic iconography reperesents the
sword with two points, probably to indicate its magical power (the two points
were used to cut out the eyes of the enemy; (for a picture of a two-pointed
sword see V. Monteil, in REI, 1940/i-ii, 22). Dhu ‘l-Fakar also
became a personal name often used by Shiites”.
The explanation of the two points also reads that, as a preparation
of the assault on Ali (661) the sword was fixed in its sheath with a rivet.
Ali draw his sword with such a force that the blade was split by the rivet.
Such a sword is seen on this 14t century picture of Ali.
The Investiture of ‘Ali at Ghadir Khumm, from the Kitab
al-athar al-baquya ‘an al-qurun al-khaliya (Chronology of Ancient
Nations), copied by Ibn al-Kutbi, northwestern Iran or northern Iraq, a.h. 707/ a.d. 1307-08. Fol. 162r; ink, colors, and gold on paper.
Edinburgh University Library (MS Arab 161) Detail.
Dhu’l-Fakar is the arms of Islam in the most literally sense of the word. It has been used by those commanders who called themselves “Sword of the commander of the Faithful” (sayf amir al-mu’minin) the servants of the caliphs who bore the title of amir al mu’minin since the accession of Umar in 634. In a broader sense the sword can be seen as the emblem of the Islamic armed forces in general. For that reason the Sword of Islam occurs on standards like banners and flags but on the other hand these flags can also be meant to be a personal badge or emblem of those princes who considered themselves to be defenders of the faith.
Flag of “Silvana”
An example from the 14th century of the Sword of Islam on a banner is on the “arms”of the ruler of “Silvana” probably Astrachan, then a part of the Empire of the Golden Horde of Uzbek Khan (1313-’41) and his successors. On these arms the background is green, the sword red with a golden hilt. 
From the beginning of the 16th century the Sword of Islam occurs in the Ottoman Empire. Probably this has a relation with the capture of Egypt by Selim the Grim in 1517. As a result of this conquest the last caliph, Al Muttawakil III (†1538) came under Ottoman authority.  From that time the two-bladed sword is on the Great Army banner, the oldest from the time of Selim I the Grim (1512-’20) himself. 
The Great Army banners were always unica. When one was lost a new one was made. The Great Banners in West-European collections were always captured from Ottoman armies.
From this it may be clear that the symbol of the, and later of a Islamic armed force is the Sword of Islam. As a badge of rank it is the emblem of a commander calling himself Sword of the Faithful. In that sense the Sword of Islam can be compared with the christogram of the Christian Roman Empire of Constantine the Great.
Flags charged with a Sword of Islam are the flags of the highest ranking officer in the Islamic military hierarchy. In some cases these flags have become the national flags, for example in Yemen (1927) and Saudi Arabia (1946).
The Two-bladed Sword
Flag of Sultan Selim I
Sarayi Muzesi, N° 824.
On the flag is the Sword of Islam and some texts from the Quran. The field is strewn with little suns radiant which are the symbols of the Ottoman Empire. The sword is between four crescents-and-suns which are the symbols of the Ottoman State. At the mast end are another two crescents, probably with the tughra of the vizier or supreme commander of the army.
Flag of Sultan Ibrahim of Selangor, 1786.
On the Flag Chart of Engel
Hoogerheyden, showing the flags captured at the battle of Selangor.
(Maritme Museum Amsterdam)
The flag, on the flag-chart numbered 9 (the last of the first row), is blue, with the double-bladed sword of Islam,between two bordures chevronny Argent, Sable, Gules and Sable
Flag of Hamuda, 5th Bey of
A flag with a Dhu ‘l-Fakar was introduced in Tunisian by Hamuda, the
5th Bey.  This flag is not the emblem of rank of a Beylerbey
of the Ottoman Empire but of a commander of a independent army. A somewhat simplified
form of this flag was flown by the Bey until the end of the monarchy in 1957.
The flag is dived in three horizontal breadths, the upper and lower
ones barry of yellow and red / red and yellow, each bar charged with suns and
crescents. The centyral breadth is green, strewn with red and yellow stars or
suns and charged with a two-bladed sword. 
Flag of the Afsharid Dynasty (1736-1749)
This flag is depicted on the Nieuwe Tafel van alle de Zeevarende
Vlaggen des Werelts from the middle of the 18th century. The flag has
five breadths blue-yellow-green-yellow-blue, the blue breadths charged with
suns and crescents for the empire and
the state. The yellow breadths are charegd with red square crosses for the
administration and the central breadth
with a sword for the armed authority
or chief commander. L.: Pav: du Mogol des Perses.
Flag of S. Soeleman Ali Iskandar Sjah (1836-‘57) of Aceh
inv. nr. NG-1977-279-2 (loan Museum Bronbeek, Arnhem). 
About 1839: Red, a white sword and at the upper mast end a whte disc. All over the flag are inscriptions in arab script cursing the Dutch.
Ensign, National and Merchant Flag of the Kingdom of Yemen
The kingdom flew a red flag charged with a white sword between five five-pointed stars. The flag which has a relious meaning was adopeted in 1927. The five stars are for the five provinces and the five principles of Islam: Prayer, Fasting, Pilgrimage, Belief in God and the Giving of Alms. The sword is the traditional symbol of the blood versed in battle. 
© Hubert de
Updated 2010.07.05; 2011.06.06
 Originating from Babylon and today in the Vorderasiatische Museum in Berlijn.
 7th - 8th century. Silver dish with moon-cart Æ 21,6 cm. Origin: Found in
1907 near Klimova village in Perm. Museum the Hermitage, St. Petersburg. Inv.
 Hofkunst van de Sassanieden. Brussel, 1993, pp. 177-179.
 Coll. American Numismatic Society.
 The next section from Encyclopaedie of Islam, New edition Dhu’l-Fakar q.v..
 Book of the Knowledge of all the Kingdoms, Lands and Lordships that are in the World. Works issued by the Hakluyt Society, 2nd series N° XXIX, 1912, p. 61: “From Maxar I went to the kingdom of Siluana which they call Septem Castra and the Greeks call it Horgiml. It is encircled by two great rivers, the Turbo and the Lusim. In this kingdom there is a great city called Sarax. The king has for device a green flag with a red scimitar.” Dit „Siluana” has to be situated between the Ural and the Wolga. The capital of the Golden Horde was Sarai.
 Al-Mutawakkil III was brought to Istanbul by Selim the Grim but he returned to Cairo where he died. There is no proof that the Ottoman Sultans claimed the caliphate after his death..
 Topkapi Sarayi Muzesi, n° 824.
 Hugon, Henri Les
Emblèmes des Beys de Tunis. Paris, 1913.
 From Smith, Flags of the World.
 De Nederlandse Ontmoeting met Azië. Amsterdam, 2002, pp. 333-334.
 Hesmer, K.-H.: Flaggen,
Wappen, Daten. Die Staaten der Erde von A-Z. Bertelsmann Lexicon-Verlag. Gütersloh,
1975., 1975, p. 102.