The Mughal expansionist tendencies sowed seeds of animosity with the Ahoms. A desire for political supremacy and territorial expansion in the northeast appears to have been a guiding motive of the Mughals under Emperors Jahangir, Shah Jahan and Aurangzeb. The rich natural resources of Assam enhanced Mughal greed. Between 1615 and 1682, the fortunes of both the Ahoms and the Mughals fluctuated. By the end of the 17th century, the Mughals had lost their hold over northeastern India due to persistent military defeats. The Ahoms, on the other hand, extended and consolidated their influence in Assam, right up to the Manas River, which remained the western boundary of their kingdom until the British East India Company arrived in 1826.