There are about 50 more or less famous people named William Davis mentioned in Wikipedia alone; in politics, sports, arts and manufacturing. You will have to be more specific.
William Davis Ardagh died in 1893.
William Stearns Davis died in 1930.
William Stearns Davis was born in 1877.
William T. Davis was born in 1862.
William Davis Ardagh was born in 1828.
William Davis - miner - was born in 1887.
William Davis - miner - died in 1925.
William Davis - bishop - was born in 1908.
William Davis - bishop - died in 1987.
William Heath Davis was born in 1822.
William Heath Davis died in 1909.
William Davis Daly died in 1900.