The next ruler, Mozaffar al-Din Shah Qajar (r. 1896–1907), ascended the throne at a time of mounting debt and social unrest. His extravagant European trips and costly lifestyle deepened Iran’s financial crisis, leading him to grant further concessions to foreign powers. Discontent among the intelligentsia, merchants, and the ulama culminated in the Iranian Constitutional Revolution (1905–1911).
In 1906, after widespread protests and strikes, Mozaffar al-Din Shah agreed to establish a constitution and a national assembly (Majlis). The Constitution of 1906 introduced the principles of limited monarchy, rule of law, and parliamentary sovereignty — revolutionary concepts for the time. The first Majlis convened in October 1906, marking the birth of modern Iranian constitutionalism.
However, Mozaffar al-Din Shah died soon after, and his successor, Mohammad Ali Shah (r. 1907–1909), attempted to roll back the revolution. Supported by Russia, he bombarded the Majlis building in 1908, triggering a civil war between royalists and constitutionalists. The latter eventually triumphed, forcing Mohammad Ali Shah into exile in Russia in 1909. His young son, Ahmad Shah Qajar (r. 1909–1925), was installed as the new monarch.
