American researcher Robert Massie, Pulitzer Prize winner and author of a number of books on the history of Russia, died aged 90, AP reported. 

According to the historian’s relatives, he suffered from Alzheimer's. Massey died at his home in Arvington, New York.

Massie became famous for the book Nicholas and Alexandra, published in 1967, about the Russian Emperor Nicholas II. It was later filmed.

Massey was born in 1929 in the city of Lexington, Kentucky. He studied American and European history at Yale and Oxford Universities.