According to Fan S. Noli George and his brothers Ivan and Gojko were nephews of Skanderbeg from his sister Jelena[7] who married Pavle Balšić.

[8] Genealogy of Kastrioti family written by Karl Hopf does not present the information about George Strez Balšić being a son of Skanderbeg's sister Jelena.

[10][11] In 1451 after Alfonso signed the Treaty of Gaeta with Skanderbeg, he signed similar treaties with George Strez Balšić and other chieftains from Albania: Gjergj Arianiti, Gjin Muzaka, Peter Spani, Pal Dukagjini, Thopia Muzaka, Peter of Himara, Simon Zenebishi and Carlo II Tocco.

[12][dubious – discuss] According to Albanian historians Kristo Frashëri and Fan Noli, Strez Balšić betrayed Skanderbeg by selling the fortress he controlled (Modritza) to the Ottoman Empire in spring 1457.

)Later on Alphonse concluded similar treaties with George Araniti, Ghin Musachi, George Strez Balšić, Peter Spani, Paul Ducaghini,...Nikola und Paul Dukagjin, Leka Zaharia von Dagno, Peter Span, Herr der Berge hinter Drivasto, Georg Strez Balsha sowie Johann und Gojko Balsha, die sich zwischen Kruja und Alessio festgesetzt hatten, die Dushman von Klein-Polatum sowie Stefan (Stefanica) Crnojevic, der Herr der Oberzeta