Slavery is a legal or economic system in which principles of property law are applied to humans allowing them to be classified as property, to be owned, bought and sold accordingly, and they cannot withdraw unilaterally from the arrangement. While a person is a slave, the owner is entitled to the productivity of the slave's labour, without any remuneration. The rights and protection of the slave may be regulated by laws and customs in a particular time and place, and a person may become a slave from the time of their capture, purchase or birth.