164 THE CONQUEST OF BENGAL

the Bengal governors paid little obedience and less rev- enue to Delhi. ]Jnder Murshid Kuli Khan, a man of considerable ability, the governorship became hereditary in the usual fashion; but in 1742 his grandson was overthrown and slain by Ali Vardi Khan, an Afghan adventurer who raised himself from a very humble post to be deputy- governor of Behar, and who won for himself by the sword the rulership of Bengal. During the fourteen years of his strong administration, the foreign mer- chants had no great reason to complain; for although he levied large subsidies from the English, French, and Dutch factories, he gave them protection and enforced good order, suppressing all quarrels and tolerating no encroachments. On his death, in 1756, he was succeeded by his adopted son, known in English histories as Siraj- ad-daulah, although the accurate spelling is said to be Chiragh-ad-daulah, a young man whose savage and suspicious temper was controlled by no experience or natural capacity for rulership, and who had long been jealous of the English, whom he suspected of having corresponded with a possible rival against him for the succession. The new Nawab had just been proclaimed, when let- ters reached Calcutta from England informing the president that, as war with France was expected, he should put his settlement into a state of defence; where- upon he began to strengthen the fortifications. But the right to fortify their places had not been conceded to the English in Bengal; and the Nawab, to whom some