Cert-money, or head-money, was a common fine, paid annually by the residents of several manors to the lords thereof; and sometimes to the hundred; pro certo letae, for the certain keeping of the leet.
This in ancient records, was called certum letae.
[1] This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed.
Cyclopædia, or an Universal Dictionary of Arts and Sciences (1st ed.).
James and John Knapton, et al.