Among the freed slaves, two very different types of music developed from the African rhythms that had formed the basis for the Negroes' work songs. One line of musical development led to the creation of religious songs, which were called spirituals. The other produced songs that were not religious, but worldly; these songs were called blues. In the years following the end of the Civil War in 1865, a whole new musical world opended up to the freed Negroes. They were able to use professionally-made wind instruments. Many of these were horns that had been left behind by soldiers in the northern and southern armies. Through these horns, they developed a rhythm they had never had before. The horns also gave the players the addition of two "blue" notes--- a flattened third and a flattened seventh. This became a basic characteristic of jazz. 1. Spirituals and blues were religious songs developed out of African rhythms.