Mohammad Reza Pahlavi (26 October 1919 – 27 July 1980) held numerous titles and honours, both during and before his time as Shah of Iran.
From his father's accession to the throne, on 15 December 1925, until his own accession, on 16 September 1941, Mohammad Reza held the style and title of His Imperial Highness The Crown Prince.
Mohammad Reza deliberately chose to crown himself as Shah ('King'), rather than Shahanshah ('King of Kings'), pledging that he would not do so until he turned Iran into a prosperous and modernised nation.
On the 26th year of his reign, in 1967, his imperial coronation ceremony took place and he was elevated to the title of Shahanshah.
[1] On 15 September 1965, Mohammad Reza was granted the title of Aryamehr ('Light of the Aryans') by an extraordinary session of the joint Houses of Parliament.