to uncover spies sent against him, and claims that the chancery was established so that Ibn Tulun could check up on every piece of correspondence with the caliphal court. Unsurprisingly, given his own origins as a slave soldier, Ibn Tulun's regime was in many ways typical of the " system" that became one of the two main paradigms of Islamic polities in the 9th and 10th centuries, as the Abbasid Caliphate fragmented and new dynasties emerged. These regimes were based on the power of a regular army composed of , but in turn, according to Hugh Kennedy, "the paying of the troops was the major preoccupation of government". It is therefore in the context of the increased financial requirements that in 879, the supervision of the finances in Egypt and Syria passed to Abu Bakr Ahmad ibn Ibrahim al-Madhara'i, the founder of the al-Madhara'i bureaucratic dynasty that dominated the fiscal apparatus of Egypt for the next 70 years. Although, as Zaky M. Hassan notes, "fragmentary evidence does not permit a thorough assessment of Tulunid economic and financial policies", it appears that the peace and security provided by the Tulunid regime, the establishment of an efficient administration, and repairs and expansions to the irrigation system, coupled with a consistently high level of Nile floods, resulted in a major increase in revenue. By the time of Ibn Tulun's death, income from the land tax alone had risen from 800,000 dinars under Ibn al-Mudabbir to the sum of 4.3 million dinars, and Ibn Tulun bequeathed his successor a fiscal reserve of ten million dinars. Crucial to this was the reform of the tax assessment and collection system, including the introduction of tax farming—which at the same time led to the rise of a new landholding class. Additional revenue was collected from commercial activities, most notably textiles and in particular linen. Ibn Tulun's regime was highly centralized, but also featured "consistent attempts to win the backing of Egypt's commercial, religious and social élite", according to Zaky M. Hassan. Notably, the wealthy merchant Ma'mar al-Jawhar functioned both as Ibn Tulun's personal financier and as the head of an informal intelligence network through his contacts in Iraq. A further "notable characteristic" of Ibn Tulun's rule, according to historian Thierry Bianquis, was "the quality of relations it maintained with Christians and Jews"; according to a letter by the Patriarch of Jerusalem, Elias III, when he took over