hunters were required to get a court-approved affidavit to capture the enslaved person. It resulted in the creation of a network of safe houses called the Underground Railroad. Fugitive Slave Act of 1850 The Fugitive Slave Act of 1850, part of the Compromise of 1850, was a federal law that declared that all fugitive slaves should be returned to their enslavers. Because the slave states agreed to have California enter as a free state, the free states agreed to pass the Fugitive Slave Act of 1850. Congress passed the act on September 18, 1850, and repealed it on June 28, 1864. The act strengthened the federal government's authority in capturing fugitive slaves. The act authorized federal marshals to require free state citizen bystanders to aid in the capturing of runaway slaves. Many free state citizens perceived the legislation as a way in which the federal government overstepped its authority because the legislation could be used to force them to act against abolitionist beliefs. Many free states eventually passed "personal liberty laws", which prevented the kidnapping of alleged runaway slaves; however, in the court case known as Prigg v. Pennsylvania, the personal liberty laws were ruled unconstitutional because the capturing of fugitive slaves was a federal matter in which states did not have the power to interfere. Many free state citizens were outraged at the criminalization of actions by Underground Railroad operators and abolitionists who helped people escape slavery. It is considered one of the causes of the American Civil War (1861–1865). Congress repealed the Fugitive Acts of 1793 and 1850 on June 28, 1864. State laws Many states tried to nullify the acts or prevent the capture of escaped enslaved people by setting up laws to protect their rights. The most notable is the Massachusetts Liberty Act. This act was passed to keep escaped slaves from being returned to their enslavers through abduction by federal marshals or bounty hunters. Wisconsin and Vermont also enacted legislation to bypass the federal law. Abolitionists became more involved in Underground Railroad operations. Pursuit Advertisements and rewards Enslavers were outraged when an enslaved person was found missing, many of them believing that slavery was good for the enslaved person, and if they ran away, it was the work of abolitionists, with one enslaver arguing that "They are indeed happy, and if let alone would still remain so". (A new name was invented for the supposed