YĀSĀ (Turkish yasaq; Mongolian jasagh “law, decree, order”), a term used of individual edicts issued by Čengiz Khan and his successors and sometimes of the entire body of such edicts; it is frequently used in the secondary literature to designate a supposed written code, the “Great Yāsā.”

Such a code was long believed to date from Čengiz Khan’s acclamation in 1206 as “ruler of all who dwell within walls of felt,” in the wording of the Secret History of the Mongols, and attempts were made to identify its individual provisions on the basis of references in numerous primary sources (Riasanovsky, pp. 83-86; Vernadsky; Poucha).  David Ayalon demonstrated that the account of the yāsā furnished by the most frequently quoted author, the 9th/15th-century Mamluk historian Taqi-al-Din Maqrizi, was derived, not from his supposed informant Ebn al-Borhān, but (without acknowledgement) from the encyclopedist Ebn Fażl-Āllāh ʿOmari (d. 749/1349) and through him, ultimately, from ʿAṭā-Malek Jovayni (d. 681/1283, q.v.).  Although ʿOmari’s account of the yāsā also incorporated material absent from the extant version of Jovayni’s history and of doubtful provenance, Ayalon showed that Jovayni was virtually our only source on the yāsā (Ayalon, 1971, pp. 101-40), though he still accepted the historicity of a written code.

David Morgan then demonstrated the lack of evidence for the written code.  The account in the Secret History (para. 203; tr. de Rachewiltz, I, pp. 135-36) merely described how Čengiz Khan entrusted his adopted brother, Šigi Qotoqu, with the office of chief judge (yarguči) and the task of maintaining registers of judicial decisions; there was nothing about written laws as such (Morgan, 1986).  The existence of a code might be implicit in Rašid-al-Din Fażl-Allāh’s statement that Čengiz Khan “drew up and set in order (morattab wa modawan gardānid) the yāsāq and yusun of rulership (pādšāhi)” (I, p. 288; tr., p. 101).  Such references are relatively meagre, though it should be noted that there is nothing incongruous in the possibility that edicts were written down; the Mongol chancery was issuing documents in the Uighur script well before Čengiz Khan’s death in 624/1227.

At the enthronement of Ögödei (Ukādāy) as great khan in 626/1229, Čengiz Khan’s yāsās were produced, confirmed, and declared to be unalterable.  They were similarly produced at the enthronement of subsequent great khans or on the eve of a major military expedition, which was required to proceed with the destruction of cities and districts according to its instructions (Jovayni, I, pp. 17-18, 149; tr., I, pp. 25, 189-90; de Rachewiltz, pp. 94-95).  From this point onwards, if not previously, what had originally been in many cases ad hoc rulings by the great conqueror acquired permanent force; they appear to have been regarded, if not as a homogeneous and systematically organized code, at least as a recognizable corpus of regulations for the governance and preservation of the empire.  The term yāsā was used in this sense by Ögödei’s son and successor, Güyük (also Koyuk), in an ultimatum to Pope Innocent IV in 644/1246 (of which the original was written in Persian) that required him to appear in person at the Mongol imperial headquarters in order that “we might cause him to hear every command that there is of the yāsā” (har farmān-e yāsā ke bāšad bešenavim: Pelliot, p. 17; de Rachewiltz, pp. 100-101).  Yet this corpus was evidently not viewed as finite, since at his accession Güyük himself issued an edict that affirmed the inviolability of not merely Čengiz Khan’s yāsās, but also those of Ögödei (Jovayni, I, p. 211; tr., I, p. 256). 

Some uncertainty exists regarding the scope of the yāsā.  From Jovayni’s chapter on the laws framed by Čengiz Khan, we might deduce that it dealt primarily with matters of governance, military discipline, the postal courier system (yām), and the conduct of the annual winter hunt (Jovayni, I, pp. 16-25; tr., I, pp. 23-34).  But he also mentions a yāsā ordering the conqueror’s descendants to treat all faiths even-handedly (I, pp. 18-19; tr., I, p. 26).  Although Ayalon rightly emphasized the futility of attempts to reconstruct the yāsā, a fuller idea of the range of edicts can be gleaned from the accounts of Western European visitors to the Mongol empire.  According to Innocent IV’s envoy Plano Carpini, one of these edicts (leges et statuta) prohibited any member of the imperial dynasty from taking the imperial throne without election by the rest of the princes; another forbade the Mongols to make peace with any nation that had not submitted (Carpini, p. 264; tr., p. 25).

Whereas Carpini for the most part treats law and custom separately (pp. 239-40; tr., p. 11; cf., on the offense of adultery, p. 250: legem ... sive consuetudinem, tr. p. 17: “law or custom”), in the Persian sources the word yāsā often appears closely linked with custom and tradition (ʿādat, āḏin, āʾin; e.g., Jovayni, I, pp. 161, 203-4, 211, 227, III, p. 3; tr., pp. 204, 248, 255, 272; II, p. 549; Rašid al-Din, II, p. 685).  Certain steppe customs were in direct conflict with the Šariʿa (religious rules and regulations).  The sources assert, for instance, that Muslims were ordered, on pain of death, to slaughter animals in accordance with Mongol practice rather than in their customary fashion.   They were forbidden to perform their canonical ablutions or, during the spring and summer months, to wash garments in running water (actions that were believed to offend local spirits and provoke their retaliation).  Such transgressions are the subject of a number of anecdotes designed primarily to highlight Ögödei’s clemency in the face of his brother Čaḡatāy’s grim determination to uphold the law (Jovayni, I, pp. 161-62, 163; tr., I, pp. 204-5, 206).  We are told that Čaḡatāy was especially zealous in enforcing the yāsā regarding the killing of animals, with the result that no one dared slaughter sheep in Khorasan, and Muslims were obliged to eat carrion (Jovayni, I, p. 227; tr., I, p. 272).

There are two separate questions at issue in this context.  The first is whether Muslim authors confused law and custom (yosun), which were in reality quite distinct: yāsā had to do with matters of governance, military affairs, and the postal relay-system, and yosun embraced merely steppe traditions and taboos regarding, for instance, diet, washing, and social relationships (Aigle, 2004a, pp. 47-48; idem, 2004b, p. 972).  Such confusion seems improbable.  Two of our principal Muslim sources are Jovayni and Rašid-al-Din.  Jovayni visited the Mongolian homeland, and Rašid-al-Din obtained much of his information from the Mongol grandee Pulād (Bolod) Čingsāng, who is less likely to have been prey to misapprehension in this context.  Moreover, any confusion, if it indeed existed, could well have arisen from the readiness of the Mongols to enforce custom as law.  To what extent they did so is the second issue.  It is certainly difficult to understand how the Muslim slaughter ritual could have been prevented in the Islamic world at large; significantly, the relevant anecdotes retailed by Jovayni (e.g., I, pp. 161-63; tr., I, pp. 204-7) are all set in the vicinity of Ögödei’s court in Mongolia.  In all probability, such taboos were enforced only when infringed publicly or in circumstances when infringement was deemed to threaten the immediate security of the great khan or his family by provoking malevolent spirits (Aigle, 2004a, pp. 69-70; idem, 2004b, pp. 993-94).

We do not know how long these measures were in force in the various parts of the empire.  An edict of the Great Khan Qubilāy in China in 1280, renewing the prohibition of the Muslim slaughter ritual (and additionally forbidding circumcision), mentions the laxity of the imperial regime in this regard since Güyük’s day.  It also refers to the issue of a similar edict in Iran by Qubilāy’s brother, the Il-khan Hülegü (Hulāgu; Cleaves, pp. 67-89).  There is, however, no evidence that it was continued.  Qubilāy’s own clampdown on the Muslims lasted only until 1287.  Directed against a relatively small, if nevertheless significant, minority of the subject population, it was perhaps easier to implement there than in the Il-khanate domain. 

Ebn Fażl-Allāh ʿOmari maintained that the yāsā was observed more steadfastly in the Chaghatayid khanate and in the Great Khan’s dominions than in the Il-khanate or the Golden Horde territories (p. 41; tr., pp. 118-19).  Whether this refers to the content of particular edicts or to the entire body of Mongol law is unclear; but it seems to class together the two Mongol states whose rulers had converted to Islam.  Authors writing under the Muslim Il-khans are at pains to stress their rulers’ allegiance to the yāsā simultaneously with their commitment to Islam.  Thus Rašid-al-Din describes the newly converted Gāzān Khan as an expert on the yāsā since his youth (II, p. 1210; tr., p. 417).  This may reflect the sensitivity of a court historian both to the notion that his sovereign’s conversion was skin-deep, a charge leveled in particular by the Mamluk enemy, and to the view of Mongols of the old school that conversion entailed abandoning the yāsā.  Certainly another royal convert to Islam, the Chaghatayid khan Tarmaširin (d. 735/1334), is said to have rejected it in favor of the Šari‛a (Ṣafadi, X, p. 383; cf. Ayalon, 1971, pp. 178-79, citing Ebn Ḥajar ʿAsqalāni).  He was overthrown, on the grounds that he had acted contrary to Čengiz Khan’s yāsā.  Ebn Baṭṭuṭa (tr. Gibb, III, p. 565; tr. Mowaḥḥed, I, pp. 422-23) identifies his precise offense as the failure to visit the eastern tracts of the khanate and summon an annual assembly (qorultāy) of notables; but it is conceivable that in his endeavors to promote Islam he had contravened another of Čengiz Khan’s edicts, namely that forbidding the Mongols to favor one faith over any other (see above).

Whatever the historical realities of the 13th century, later decades witnessed the growth of a widespread belief that Čengiz Khan had promulgated a written code of laws, the yāsā.  In the Mamluk sultanate, which posed as the defender of Islam against the infidel Mongols and was on hostile terms with the Il-khanate until 723/1323, great stress was laid on the opposition between the yāsā and the Šariʿa, and discussion of the yāsā was of a polemical nature.  As a consequence various provisions were attributed to Čengiz Khan’s yāsā which were surely apocryphal, such as those listed by the hostile 9th/15th-century witness, Ebn ʿArabšāh (Irwin, pp. 8-9).  There is no evidence to support the claim by Ṣafadi (d. 764/1363) that the Mongol mamluk Aytemeš administered the affairs of the Sultan’s personal mamluks according to the yāsā (Ṣafadi, IX, p. 440; cf. Little, 1979), and the role of the yāsā within the Mamluk dominions in practice has been greatly exaggerated.  Maqrizi’s principal aim in speaking of it was to accuse the military chamberlains (ḥojjāb) of extending it to cases that involved ordinary Muslims and that properly pertained to the Šariʿa and the jurisdiction of the judge (qāżi).  It has been shown that this charge was, in fact, groundless and that what was at stake was merely the application of siāsa, namely the justice administered by the sultan and his officers independently of the Šariʿa (Maqrizi, II, pp. 40-41, 208, 219; Ayalon, 1973, pp. 119-42).

The Turco-Mongol conqueror Timur (r. 771-807/1370-1405), who set out to recreate the empire of Čengiz Khan, combined Islamic zeal with a strong attachment to Mongol traditions, including the yāsā.  His court historian Neẓām-al-Din Šāmi thought it worthwhile, when inflating the importance of Timur’s ancestor Qarāčār in the Chaghatayid state, to depict him as the guardian of the yāsā (Šāmi, I, pp. 10, 12-14, 58; Manz, 1988, p. 111).  Although Timur’s son Šāhroḵ is said to have rejected the yāsā and implemented only Islamic law, the most he did was to promote Islamic norms while preserving an allegiance to the Mongol heritage (Manz, 2001, p. 144).  During the 9th/15th and 10th/16th centuries Central Asia was the scene of controversy over the proper place of the yāsā, or tura/töre (rule, usage), as it was usually known there, and its relation to the Šari‛a, especially following the boost given to Chengizid charisma by the rise of the Uzbeks and their conquest of Transoxiana (McChesney, 1990, pp. 63-80; idem, 1996, pp. 127-32).  In his autobiography, the first Mughal emperor, Bābor, denied the binding character of the tura where its stipulations were at fault (Dale, p. 171).  Evidence regarding the character of the yāsā from these eastern regions is doubtless more reliable, on balance, than that emanating from the western Islamic world, though still in some cases problematic.  For instance, Bābor’s contemporary, the Uzbek khan Moḥammad Šibāni, believed that one of Čengiz Khan’s yāsās prescribed the right of a grandson whose father was dead to inherit an equal share of the property with his uncles; but we have no evidence to confirm its authenticity for the 7th/13th century (Isogai, p. 93).


Primary sources. 

John of Plano Carpini, Ystoria Mongalorum, ed. Enrico Menestò, Claudio Leonardi, and Maria Cristiana Lungarotti, as Giovanni del Pian di Carpine: Storia dei Mongoli, Spoleto 1989; tr. in Christopher Dawson, The Mongol Mission: Narratives and Letters of the Franciscan Missionaries in Mongolia and China in the Thirteenth and Fourteenth Centuries, London, 1955, pp. 1-72.

ʿAlāʾ-al-Din Aṭā-Malek Jovayni, Tāriḵ-e jahāngošāy, ed. Moḥammad Qazvini, 3 vols., Leiden, 1912-37, pp. 16-25; tr. John Andrew Boyle, as The History of World Conqueror, 2 vols., Manchester, 1958, I, pp. 23-34.

Ebn Baṭṭuta, Toḥfat al-noẓẓār fī ḡarāʾeb al-amṣār wa ʿajāʾeb al-asfār, ed. and tr. Hamilton A. R. Gibb and Charles F. Beckingham, as The Travels of Ibn Battuta, 5 vols., Cambridge, 1958-2000; tr. Moḥammad-ʿAli Mowaḥḥed, as Safar-nāma-ye Ebn Baṭṭuṭa, 2 vols., Tehran, 1969.

Ebn Fażl-Allāh ʿOmari, Masālek al-abṣār, ed. and tr. Klaus Lech, as Das mongolische Weltreich: al-ʿUmari's Darstellung der mongolischen Reiche, Wiesbaden, 1968, esp. Arabic text, pp. 7-10, Ger. tr., pp. 95-97.

Taqi-al-Din Abu′l-ʿAbbās Maqrizi, al-Mawāʿeẓ wa’l-eʿtebār fi ḏekr al-ḵeṭaṭ wa’l-ātār, 2 vols, Bulāq 1270/1853-54.

Rašid al-Din Fażl-Allāh, Jāmeʿ al-tawāriḵ, ed. Moḥammad Rowšan and M. Musawi, Tehran, 1994; tr. Wheeler M. Thackston, as Classical Writings of the Medieval Islamic World:  Persian Histories of the Mongol Dynasties: Jamiʿu’t-Tawarikh: A Compendium of Chronicles by Rashiduddin Fazlullah, 3 vols., London and New York, 2012. 

Ṣalāḥ-al-Din Ḵalil b. Aybak Ṣafadi, al-Wāfi be’l-wafayāt, ed. H. Ritter et al., as Das biographische Lexikon des Ṣalāḥaddīn Ḫalīl b. Aibak aṣ-Ṣafadī, 28 vols. (out of 30), Istanbul, Leipzig, Wiesbaden, etc. 1931-2004.

Neẓām-al-Din Šāmi, Ẓafar-nāma, ed. Felix Tauer, Histoire des conquêtes de Tamerlan intitulée Ẓafarnāma par Niẓāmuddīn Šāmī, 2 vols., Prague 1937-56.

The Secret History of the Mongols: A Mongolian Epic Chronicle of the Thirteenth Century, tr. Igor de Rachewiltz, 2 vols., Leiden, 2004.


Denise Aigle, “Le Grand Jasaq de Gengis-Khan: l’empire, la culture mongole et le Shariʿa,” Journal of the Economic and Social History of the Orient 47/1, 2004a, pp. 31-79. 

Idem, “Loi mongole vs loi islamique:  Entre mythe et réalité,”  Annales. Histoire, Sciences Sociales 59, 2004b, pp. 971-96.

Reuven Amitai-Preiss, “Ghazan, Islam and Mongol Tradition: A View from the Mamlūk Sultanate,” BSOAS 59, 1996, pp. 1-10; repr. in idem, The Mongols in the Islamic Lands: Studies in the History of the Ilkhanate, Aldershot, UK, 2007. 

Françoise Aubin, “Some Characteristics of Penal Legislation among the Mongols (13th-21st Centuries),” in Wallace Johnson and Irina Fedorovna Popova, eds., Central Asian Law: An Historical Overview.  A Festschrift for the Ninetieth Birthday of Herbert Franke, Lawrence, Kans., 2004, pp. 119-51. 

David Ayalon, “The Great Yāsa of Chingiz Khan: A Re-examination,” Studia Islamica 33, 1971, pp. 97-140; 34, 1971, pp. 151-80; 36, 1972, pp. 113-58; 38, 1973, pp. 107-56; repr. in  idem, Outsiders in the Lands of Islam: Mamluks, Mongols and Eunuchs, London, 1988. 

Michal Biran, “The Chaghadaids and Islam: The Conversion of Tarmashirin Khan (1331-34),” JAOS 122, 2002, pp. 742-52. 

Clifford Edmund Bosworth and David O Morgan, “Yāsā,” in EI2 XI, 2002, pp. 293-94.

Francis Woodman Cleaves, “The Rescript of Qubilai Prohibiting the Slaughtering of Animals by Slitting the Throat,” in Carolyn I Cross, ed., Richard Nelson Frye Festschrift I:  Essays Presented to Richard Nelson Frye on His Seventieth Birthday by His Colleagues and Students, Cambridge, Mass., 1992 = Journal of Turkish Studies 16, pp. 67-89.

Stephen Fredric Dale, The Garden of the Eight Paradises: Bābur and the Culture of Empire in Central Asia, Afghanistan and India (1483-1530), Leiden, 2004. 

Gerhard Doerfer, Türkische und mongolische Elemente im Neupersischen, 4 vols., Wiesbaden 1963-75, I, pp. 264-67 (no. 134: törä), 555-7 (no. 408: yōsūn), and IV, pp. 71-82 (no. 1789: yāsāq). 

Robert G. Irwin, “What the Partridge Told the Eagle: A Neglected Arabic Source on Chinggis Khan and the Early History of the Mongols,” in Reuven Amitai-Preiss and David O. Morgan, eds, The Mongol Empire and Its Legacy, Leiden 1999, pp. 5-11. 

Kenichi Isogai, “Yasa and Shari‛a in Early 16th Century Central Asia,” in Maria Szuppe, ed., L’Héritage timouride  Iran —  Asie centrale — Inde XVe-XVIIIe siècles, Cahiers d’Asie Centrale 3-4, Tashkent and Aix-en-Provence, 1997, pp. 91-103. 

D. P. Little, “Notes on Aitamiš, A Mongol mamlūk,” in Ulrich Haarmann and Peter Bachmann, eds, Die islamische Welt zwischen Mittelalter und Neuzeit: Festschrift für Hans Robert Roemer zum 65. Geburtstag, Wiesbaden 1979, pp. 387-401; repr. in Little, History and Historiography of the Mamlūks, London 1986.

Beatrice Forbes Manz, “Tamerlane and the Symbolism of Sovereignty,” Iranian Studies 21, 1988, pp. 105-22. 

Idem, “Mongol History Rewritten and Relived,” Revue des Mondes Musulmans et de la Méditerranée 89-90, 2001, pp. 129-49. 

Robert D. McChesney, “Zamzam Water on A White Felt Carpet: Adapting Mongol Ways to Muslim Central Asia, 1550-1650,” in Michael Gervers and Wayne Schlepp, eds, Religion, Customary Law, and Nomadic Technology, Toronto 1990, pp. 63-80.

Idem, Central Asia: Foundations of Change, Princeton 1996. 

David O. Morgan, “The ‘Great Yāsā of Chingiz Khān’ and Mongol Law in the Īlkhānate,” BSOAS 49, 1986, pp. 163-76. 

Idem, “The ‘Great Yasa of Chinggis Khan’ revisited,” in Reuven Amitai and Michal Biran, eds, Mongols, Turks, and Others: Eurasian Nomads and the Sedentary World, Leiden, 2005, pp. 291-308. 

Idem, The Mongols, 2nd ed., Oxford, 2007, pp. 83-87. 

Paul Pelliot, “Les Mongols et la papauté,” part I, Revue de l’Orient Chrétien 23, 1922-23, pp. 3-30. 

P. Poucha, “Über den Inhalt und die Rekonstruktion des ersten mongolischen Gesetzbuches,” in Louis Ligeti, ed., Mongolian Studies, Budapest, 1970, pp. 377-415.

Igor de Rachewiltz, “Some reflections on Činggis Qan’s Jasaγ,” East Asian History 6, December 1996, pp. 91-104.  

Paul Ratchnevsky, “Die Yasa (Jasaq) Činggis-khans und ihre Problematik,” in Györgi Hazai and Peter Zieme, eds, Sprache, Geschichte und Kultur der altaischen Völker, Berlin 1974, pp. 471-87. 

Idem, Cinggis-Khan, sein Leben und Wirken, ed. and tr. Thomas Nivison Haining, as Genghis Khan: His Life and Legacy, Oxford 1991, pp. 187-96. 

Valentin Alexandrovich Riasanovsky, Fundamental Principles of Mongol Law, Tientsin, 1937; repr., Bloomington, Ind., and The Hague, 1965, esp., pp. 83-86. 

George Vernadsky, “The Scope and Content of Chingiz Khan’s Yasa,” HJAS 3, 1938, pp. 337-60.

(P. Jackson)

Originally Published: December 13, 2013

Last Updated: December 13, 2013

Cite this entry:

P. Jackson, “YĀSĀ,” Encyclopædia Iranica, online edition, 2013, available at http://www.iranicaonline.org/articles/yasa-law-code (accessed on 20 September 2016).