Watt. Muhammad at Medina. pp. 227-228 Watt argues that the initial agreement came about shortly after the hijra and that the document was amended at a later date – specifically after the battle of Badr (AH [anno hijra] 2, = AD 624). Serjeant argues that the constitution is in fact 8 different treaties which can be dated according to events as they transpired in Medina, with the first treaty written shortly after Muhammad's arrival. R. B. Serjeant. "The Sunnah Jâmi'ah, Pacts with the Yathrib Jews, and the Tahrîm of Yathrib: Analysis and Translation of the Documents Comprised in the so-called 'Constitution of Medina'." in The Life of Muhammad: The Formation of the Classical Islamic World: Volume iv. Ed. Uri Rubin. Brookfield: Ashgate, 1998, p. 151 and see same article in BSOAS 41 (1978): 18 ff. See also Caetani. Annali dell'Islam, Volume I. Milano: Hoepli, 1905, p. 393. Julius Wellhausen. Skizzen und Vorabeiten, IV, Berlin: Reimer, 1889, p 82f who argue that the document is a single treaty agreed upon shortly after the hijra. Wellhausen argues that it belongs to the first year of Muhammad's residence in Medina, before the battle of Badr in 2/624. Even Moshe Gil a skeptic of Islamic history argues that it was written within five months of Muhammad's arrival in Medina. Moshe Gil. "The Constitution of Medina: A Reconsideration." Israel Oriental Studies 4 (1974): p. 45.