Prior to the Civil War, Delaware was a slave state, but in the early 19th cent. the number of slaves in the state declined, while the number of free blacks increased. Many citizens of Delaware favored manumission of slaves and belonged to the American Colonization Society, but there were few who sympathized with the growing abolitionist movement and there was strong sentiment for separation of whites and blacks. In the Civil War, Delaware remained loyal to the Union, but pro-Southern feeling increased rather than diminished during the course of the war. Delaware refused to accept an emancipation proposal made by Lincoln in 1861 and did not ratify the Thirteenth, Fourteenth, and Fifteenth amendments to the U.S. Constitution until 1901. Delaware Democrats subsequently became divided, and the Republican Party emerged in 1905 to assume a leading political role for some years.