The Russians therefore immediately conducted a thorough statistical account of the population of the Erivan Khanate, now renamed to the "Armenian Oblast". Ivan Chopin headed the survey team which gathered the administrative census ("Kameral'noe Opisanie'") for the newly established Russian administration in Erivan. Based on the Persian administrative records of the Erivan Khanate as well as interviews, the "Kameral'noe Opisanie" is considered to be "the only accurate source for any statistical or ethnographical data" on the territories that comprised Iranian Armenia, on the situation before and immediately after the Russian conquest.