Besides these, there is a population of Predial slaves, divided and subdivided.
"The Ethnology of the British Colonies and Dependencies"
Robert Gordon Latham
Again, in the ninth and tenth centuries, pestilence and famine accelerated the extinction of Predial slavery by weakening the numbers of the free population.
"On Compromise"
John Morley
There is ample evidence to prove that there was a very general continuance of Predial services after the revolt, though they went on rapidly decreasing.
"A Short History of English Agriculture"
W. H. R. Curtler