A more thorough explanation:

A Commission of Gaol Delivery is a historical appointment given by the monarch to a judge, allowing them to travel on the assize circuit and hear all criminal cases of those held in county jails. This commission was used in England and Wales during the medieval and early modern periods.

For example, if a person was accused of a crime and held in a county jail, the judge appointed by the monarch would travel to that jail and hear their case. This allowed for a fair trial and ensured that justice was served.

The Commission of Gaol Delivery was often used in conjunction with the Commission of Oyer and Terminer, which allowed the judge to hear cases that were not yet in the county jail. Together, these commissions ensured that all criminal cases were heard and justice was served.