 Several committees were established in the 1890s, largely at the behest of Thomas C. Platt and other Republicans, to investigate Tammany and Croker, including the 1890 Fassett Committee, the 1894 Lexow Committee, during which Croker left the United States for his European residences for three years, and the Mazet Investigation of 1899.Croker's greatest political success was his bringing about the 1897 election of Robert A.Van Wyck as first mayor of the five-borough "greater" New York, and during Van Wyck's administration Croker is popularly supposed to have completely dominated the government of the city.