Muhammad and his followers are said to have negotiated an agreement with the other Medinans, a document now known as the Constitution of Medina (date debated), which laid out the terms on which the different factions, specifically the Jews and other "Peoples of the Book" could exist within the new Islamic State.
The Jewish groups had refused to acknowledge Muhammad as a prophet and in the document only appear second in character. [And] the prestige of his [Muhammad] military successes [later in life] gave him almost autocratic power.
Constitution of Medina, Muhammad demanded the Jews' political loyalty in return for religious and cultural autonomy. However, after each major battle with the Medinans, Muhammad accused one of the Jewish tribes of treachery (See 2:100). After Badr and Uhud, the Banu Qainuqa and Banu Nadir, respectively, were expelled "with their families and possessions" from Medina. After the Battle of the Trench in 627, the Jews of Banu Qurayza were accused of conspiring with the Meccans; Qurayza men were beheaded, women and children enslaved, and their properties confiscated. Watt writes that some of the Arab tribe of Aws, who were allied with Qurayza before arrival of Muhammad, are said to asked Muhammad to forgive Qurayza for their sake as Muhammad had previously forgived Nadir for the sake of Abd-Allah ibn Ubayy. Muhammad met this feeling by suggesting that the fate of Qurayza should be decided by one of their Muslim allies and thereby avoiding any likelihood of blood-feud. A suggestion to which the Jews agreed. Muhammad appointed Sa'd ibn Mua'dh, a leading man among Aws, who passed execution sentence against Qurayza. Watt states that there is no need to suppose that Muhammad brought pressure on Sa'd ibn Mua'dh: Those of the Aws who wanted leniency for Qurayza seems to have been regarded Qurayza unfaithful only to Muhammad and not to Aws; the old Arab tradition required support of an ally, independent of the ally's conduct to other people. But Sa'd didn't want to allow tribal allegiance to come before the Islamic allegiance.