Who was known as Iron man of India?

Sardar Vallabhbhai Patel was called the 'Iron Man of India' for his decisive role in integrating over 500 princely states into the Indian Union after independence in 1947. As India's first Home Minister, he used diplomacy and sometimes force to convince rulers to accede. His steely resolve and administrative skills earned him this title from the press. Nehru was the first PM, Bose was a revolutionary leader, and Pant was a senior Congress leader.