On September 22, 1862, Lincoln issued a preliminary warning that he would order the emancipation of all slaves in any state that did not end its rebellion against the Union by January 1, 1863. ... The Proclamation made freeing the slaves an explicit goal of the Union war effort.
The phrase "glued to their horses" simply meant that the Huns were such skilled fighters and riders that it was very difficult to knock them off their horses during an attack.
