At the 1206 kurultai (assembly), Temüjin was proclaimed Chinggis Khan, marking the formal founding of the Mongol Empire. Later traditions associate this foundational moment with the establishment or formalization of imperial norms later grouped under the Yassa (Yasa).
Mongol narrative tradition (notably The Secret History of the Mongols) describes Chinggis Khan instructing his adopted son Shigi Qutuqu to record legal decisions and administer justice—an origin story for early Mongol judicial practice often linked to the later remembered Yassa tradition.
As the empire expanded, Mongol rulers appointed darughachi (administrators/overseers) to manage taxation and governance in subjected regions. This administrative layer helped translate imperial mandates—whether framed as yāsā or as decrees—into enforceable local practice.
Chinggis Khan’s death (1227) shifted the problem of “law” from personal rulership to dynastic governance. Later sources describe subsequent khans as reaffirming inherited ordinances and precedents associated with the Yassa while issuing new rulings and decrees.
Under Ögedei Khan, the imperial relay-post system (Yam/Örtöö) was established across the empire with staffed stations supplying mounts and provisions to authorized couriers and envoys. This infrastructure materially enabled enforcement and circulation of imperial decisions and orders at scale.
Accounts of Ögedei’s reign describe restrictions on elite abuses involving paiza (authority tablets) and jarliq (decrees), reflecting an attempt to standardize and control how privileges and orders were issued and enforced—an administrative complement to the broader yāsā tradition.
Under Ögedei, Shigi Qutuqu held senior administrative roles in North China and is associated with a general census (1235–1236). Such fiscal-administrative measures formed part of the practical implementation environment for imperial norms and rulings across diverse populations.
In the mid-13th century, Mongol-appointed administrators governed large parts of Iran prior to the formal establishment of the Ilkhanate. A documented example is Arghun Aqa, described as a key Mongol governor (darughachi) in Persia, illustrating institutional channels through which Mongol rulings were implemented.
Paiza (gerege) tablets functioned as passports/credentials used by officials, messengers, and envoys on Mongol postal routes, enabling access to horses, supplies, and services. These instruments operationalized imperial authority and helped carry legal-administrative orders across long distances.
Narratives of Möngke Khan’s reign describe efforts to limit abuses connected to privileged merchants and the misuse of authority instruments (including paiza-related privileges), illustrating ongoing attempts to regularize enforcement mechanisms within the imperial order.
In the Ilkhanate context, sources describe the yāsā (dynastic/tribal law associated with Chinggis Khan) as being applied alongside, or in tension with, Islamic sharia—showing how implementation varied by region and interacted with established legal systems.
Surviving decree/letter practices show differences in how authority was expressed: Great Khans’ documents commonly used jarliq (“qaγan’s decree”), while some regional khanates preferred other formulae (e.g., üge, “word”). This indicates how imperial legal command and its formalization evolved across successor polities.
In the early 14th century, Ilkhanid vizier-historian Rashid al-Din produced the Jāmiʿ al-tawārīkh (“Compendium of Chronicles”), a major narrative source for Mongol institutions and historical memory. Such compilations shaped later understandings of the Yassa as an imperial legal tradition.
By the 14th century, the Yasa/Yassa appears in historical and reference traditions as a body of Chinggisid dynastic law remembered and invoked within successor regimes (especially in contexts discussing Mongol governance and its interaction with local legal norms), even though the code itself is not preserved as a single complete text.
The Yassa Legal Code and Its Implementation across the Empire (1206–14th century)
