Original: Pope Leo XIII ( 2 March 1810 - 20 July 1903 ) , born Count Vincenzo Gioacchino Raffaele Luigi Pecci , was the 257th Pope of the Roman Catholic Church , reigning from 1878 to 1903 , succeeding Pope Pius IX .
Simplified: Pope Leo XIII ( March 2 , 1810 -- July 20 , 1903 ) , born Vincenzo Gioacchino Raffaele Luigi Pecci , was the 256th Pope of the Roman Catholic Church .