The Rus'–Byzantine Treaty of 911 is the most comprehensive and detailed treaty concluded between the Byzantine Empire and Kievan Rus in the 10th century. It was preceded by the preliminary treaty of 907. It is considered the earliest written source of Old Russian Law.
The text of the document, incorporated into the Primary Chronicle, has many affinities in content and phrasing with the trade treaties later concluded by Byzantium with the merchant republics of Italy. It was composed in two languages and signed personally by Emperor Leo VI. The text also includes speeches of the parties on the occasion. No treaties of comparable complexity and antiquity are known among the other societies in Europe of that time.
The treaty opens with a lengthy enumeration of the Rus' envoys (attested or reconstructed Old Norse forms in parentheses): Farlof (Farulfr), Ver/lemud (Vermu(n)dr), Rulav (Rollabʀ), Fost (*Fastuʀ), Frelavc (Frilleifr), Inegeld (Ingjaldr), Karly (Karli), Karn (Karna, attested in a Swedish runic inscription), Lidul(f) (Lidulif < Leiðulfr, but litulf is attested from a runic inscription), Ruald (Hróaldr), Rjuar (Hróarr), Truan (Þróndr or Þrandr).
The articles 3 to 7 regulate criminal law and the life of their colony at Constantinople. There is also a proviso on inheritance of a merchant who died in the imperial capital. The article 8 is dedicated to maritime law. The following articles enlarge on ransom of captives, exchange of criminals, and the status of the Varangian mercenaries in Byzantine service.
- The Nordic Languages, vol 1, p. 1041
- (in Russian) Повесть временных лет, ч. 1—2, М.—Л., 1950.
- Memorials of Russin Law. Issue 1: Memorials of Law of Kievan State 10th-12th centuries / Aleksandr Zimin. Moscow, 1952. ( (in Russian) Памятники русского права. Вып. 1: Памятники права Киевского государства X–XII вв. / Сост. А.А. Зимин. М., 1952).
- (in Russian) Fyodor Uspensky. The History of the Byzantine Empire, vol. 2. Moscow: Mysl, 1997.
- Lind, John H (2004). "Varangians in Europe's Eastern and Northern Periphery". Ennen & nyt (4). Retrieved 2009-03-13.
- Sverrir Jakobsson, The Varangians: In God’s Holy Fire (Palgrave Macmillan, 2020), pp. 38-41.ISBN 978-3-030-53797-5