Is it true that constancio guzman is the first mayor in davao. during that time they called EL Presidente?

Constancio Guzman was the second elected municipal president of Davao in 1917, during the governorship of Eulalio Causing. ( DAVAO CITY: ITS HISTORY AND PROGRESS by GLORIA P. DABBAY, 1988 edition, page 45, University of Michigan)