The legislature also worked to improve conditions in slavery in order to avoid problems; it established penalties for masters who demanded excessive work or who brutally punished slaves. These provisions were difficult to enforce, as the law did not allow slave testimony against whites. They also started a school to teach slaves Christian doctrine. At the same time, the legislature tried to prevent slaves from being manumitted, as the representatives thought that the presence of free blacks in the colony made slaves restless. It required slaveholders to apply to the legislature for permission for each case of manumission; formerly, manumissions could be arranged privately. South Carolina kept these restrictions against manumission until slavery was abolished after the American Civil War.