 As a great specialist in medieval and early modern history of Southeast Europe, he was expected to have been the first to hold the Nicolae Iorga Chair at Columbia University in New York City in the Spring semester of 1972.He authored works such as "History of Romanians", "Nomadic Populations in the Euro-Asian and the part they played in the formation of Mediaeval States", "The Making of the Romanian Unitary State", "The Making of the Romanian People and Language", "Chronological History of Romania", and "Transylvania in the History of the Rumanian People".He was the father of historian Dinu C. Giurescu.