What compromise did they agree on to settle the issue of slavery?

The question seems to refer to the compromises made in the United States during the 19th century to settle the issue of slavery. There were several key compromises:

1. Missouri Compromise (1820): This compromise admitted Missouri as a slave state and Maine as a free state, maintaining the balance of power in the Senate. It also prohibited slavery in the Louisiana Territory north of the 36° 30´ latitude line.

2. Compromise of 1850: This was a series of five bills. California was admitted as a free state, the slave trade (but not slavery) was abolished in Washington D.C., a more stringent Fugitive Slave Law was enacted, and the territories of New Mexico and Utah were allowed to decide on the issue of slavery for themselves (popular sovereignty).

3. Kansas-Nebraska Act (1854): This act allowed the territories of Kansas and Nebraska to decide on the issue of slavery for themselves (popular sovereignty), effectively repealing the Missouri Compromise.

These compromises were attempts to maintain a balance of power between slave states and free states and to keep the Union together. However, they ultimately failed to permanently resolve the issue of slavery, which was a major cause of the American Civil War.