Yardley died in 1627. Slaves were quite rare in the Jamestown settlement at that time. Most servants were English and were bound to a master by an indenture. The terms of the indenture were usually for a period of seven years after which the servant was set free and given a parcel of land and farming implements. The indenture usually paid for the cost of their passage to Virginia.
Christians could not be made slaves, but Indians could be made slaves and the settlers tried to do that, but since they could easily escape, that practice did not last. The Portuguese began the slave trade buying Africans from Africans and selling them in Brazil and later in the Caribbean and America.
Most slaves at that point in the British New World were Irish.