During first century of Russian control, this territory was settled by immigrants from original or historic Azerbaijan which located in nothern Iran with capital city of Tabriz. Russinan autority encouriged immigration from Ardebil, Hoy and Tabriz area of historic Azerbaijan of handreds of thausunds turkish speaking Azerys. This policy caused faster turkish assimiliation of the majority of local population of Lezgi, Talish, Avar, Udi, Kriz and Tats of Shervan. And also made it easier to subdue and to control local population because new comers were more loyal to Moscow. The territory of historic Shirvan and Arran is wrongly called Republic of Azerbaijan.
As is the case with many city and village names in large countries, there is often more than one city or village with the same name in different parts of Iran. Shervan/Shirvan happens to be one such case.
There is another Shervan/Shirvan in modern Iran proper, in the province of North Khorasan.
Khaghani was not Turkish. His mother was actually a Georgian christian convert to Islam.