#ond

Fresco by Bertalan Székely in the ceremonial hall of the city hall of Kecskemét, Hungary. Created between 1895 and 1897, the painting features a depiction of the bull's head bowl, from the treasure of Nagyszentmiklós

The blood oath (Hungarian: vérszerződés, lit. "blood contract") was, according to tradition, a pact among the leaders of the seven Hungarian tribes, traditionally held to be the first, unwritten constitution of the Hungarian nation. Its story, along with the terms agreed upon in it, is mostly known from the somewhat unreliable Gesta Hungarorum, a chronicle written between 1196–1203 and is thus possibly influenced by 12th century laws and customs. The oath was sealed by the seven leaders – Álmos, Előd, Ond, Kond, Tas, Huba and Töhötöm – by cutting their arms and letting their blood into a chalice. Becoming blood brothers is likely to have been used traditionally to seal exceptionally strong oaths, and there must have been several similar oaths, but the phrase "blood oath" usually refers to the one by the seven leaders.

A bull's head bowl from the treasure; this piece is known in Hungary as "Attila's Cup". 

The description of the oath taking ceremony mirrors the political and societal changes during Anonymus' lifetime. The increasing power of the nobles and their need for the codification of their rights culminated in the issuing of the Golden Bull of 1222. Several historians concluded that Anonymus' intentions in writing down this agreement were to express the societal changes during his own period, and support the fight for the rights of the nobility, as a kind of historical justification. 

According to historian István Nemeskürty, "The aim of Magister P. (Anonymus) is to justify the rights and claims of 13th century Hungarian nobility and create a lineage going back to the Conquest for all of his friends and family. Also, although Anonymus stresses that his works are based on written sources, he wanted to create a literary work in the style of his own time period."[4]