Complex sentence: After the outbreak of the mutiny in Meerut, the rebels very quickly reached Delhi, the nominal capital of nearly defunct Mughal Empire, whose ruler, Bahadur Shah Zafar, they installed as Emperor of Hindustan.
Split into simpler sentences: After the outbreak of the mutiny in Meerut, the rebels very quickly reached Delhi, the nominal capital of nearly defunct Mughal Empire. Its ruler, Bahadur Shah Zafar, was installed as Emperor of Hindustan.