A specialist on political history of the 19th century, he has written many volumes on a variety of topics, focusing on the history of Slovene–Italian border regions of Goriška and Venezia Giulia. He writes both in Slovene and Italian. He is for his studies of Slovene–Italian relations in the 19th and 20th century, and has been praised for his contributions in the cultivation of Slovene–Italian cultural and historical dialogue.[2] He was member of the Slovenian-Italian Cultural-Historical Commission, established by the governments of the two countries to shed light on the historical relationship between the two peoples from 1880 to 1954.[3]