Justice in eyre
In English law, the justices in eyre were the highest magistrates, and presided over the court of justice-seat, a triennial court held to punish offenders against the forest law and enquire into the state of the forest and its officers (eyre, meaning "circuit", refers to the movement of the court between the different royal forests). Technically, the two justices were referred to as citra and ultra Trent (on the same side or across the River Trent), depending on where the royal court was held at the time, but are usually referred to in absolute geographical terms north and south.