This manuscript slave code for the District of Columbia, commonly referred to as a practice book, was probably produced by a Washington law firm for the use of its attorneys and clerks. By Southern standards, the codes were lenient. Slaves living within the city could hire out their services and live apart from their masters, while free blacks could own and operate private schools. The slave trade (buying and selling slaves) was abolished in the District in 1850. Lincoln's signing of An Act for the release of certain persons held to service, or labor in the District of Columbia on April 16, 1862, abolished slavery (the owning of slaves) in the capital city, rendering the code obsolete.