[1] Leo adopted a critical stance in examining some of the most important issues in Armenian history, literature and contemporary problems of the early 20th century.

[4] Due to the death of his father in 1879, Leo was unable to attend university and began working to support his family.

[5] He took up several jobs in Shusha and Baku as a notary's clerk, telegraph operator, and the manager of a printing house called Aror ("Plough").

[6] In 1906, he began teaching at the Gevorgian Seminary at Ejmiatsin, although he returned to Tiflis a year later and dedicated himself to his academic work.

[3] Over the years, he wrote for various Armenian newspapers and journals, such as Mshak, Ardzagank’, Armenia, Murch, and Handes Amsorya.

[7] From about 1880 to 1900, Leo mostly wrote works of fiction, reviews, and articles on contemporary issues, whereas from 1900 onward, he focused on writing history.

[10] It devotes particular importance to the political, cultural and social issues that surrounded Armenian life and the role that Armenia's neighbors played in the country's history.

[4] After Soviet Russian writer Andrei Bitov visited Yerevan in 1960, he remarked that "he did not enter any house which did not have the familiar three volumes of Leo's History of Armenia.

Besides his historical and social-political writings, Leo also wrote some literary criticism, translations of European authors, and a number of fictional works in the style of realism.