During his reign Western science, technology, and educational methods were introduced into Iran and the country’s modernization was begun. Nāṣer od-Dīn Shāh exploited the mutual distrust between Great Britain and Russia to preserve Iran’s independence.When Nāṣer was assassinated by a fanatic in 1896, the crown passed to his son Moaffar od-Dīn Shāh (reigned 1896–1907), a weak and incompetent ruler who was forced in 1906 to grant a constitution that called for some curtailment of monarchial power.