Shah Alam II was the later Mughal Emperor who was not allowed to enter Delhi for twelve years and had to restore his throne with the help of the Marathas. Let's explore this in detail.

Background:
- Shah Alam II was born in 1728 and became the Mughal Emperor in 1759 after the death of his father, Alamgir II.
- During his reign, the Mughal Empire was in decline, with the British East India Company gaining significant power in India.
- The Marathas, a powerful Hindu empire in western India, also sought to expand their influence and control over the Mughal territories.

Shah Alam II's Exile:
- In 1759, Shah Alam II was deposed by his wazir, Imad-ul-Mulk, and forced to flee to Allahabad.
- He was not allowed to enter Delhi for twelve years and lived in exile, struggling to maintain his authority and regain his throne.
- During this period, the Marathas emerged as a significant power in northern India and sought to establish their influence over the Mughal Empire.

Restoration with Maratha Help:
- In 1771, Shah Alam II formed an alliance with the Marathas, led by Mahadji Scindia, to regain his throne.
- The Marathas, who had already established their control over parts of northern India, marched towards Delhi to restore Shah Alam II as the Mughal Emperor.
- In 1772, with the support of the Marathas, Shah Alam II was able to enter Delhi and reclaim his throne.
- However, the Marathas exerted significant influence over the Mughal Empire and Shah Alam II's authority was largely symbolic.

Consequences and Legacy:
- The restoration of Shah Alam II with the help of the Marathas marked a turning point in the Mughal Empire's decline.
- The Marathas became the de facto rulers of the Mughal territories, while Shah Alam II remained a figurehead Emperor.
- This period also witnessed increased British intervention in Indian affairs, as the East India Company gained more control over Mughal territories.
- Shah Alam II's reign continued until his death in 1806, during which the Mughal Empire further weakened and lost its authority.

Conclusion:
In conclusion, Shah Alam II was the later Mughal Emperor who was not allowed to enter Delhi for twelve years and had to restore his throne with the help of the Marathas. The alliance with the Marathas allowed him to regain his authority, although their influence over the Mughal Empire increased significantly. This event marked a significant turning point in the decline of the Mughal Empire and the increasing dominance of regional powers and European colonial forces in India.