Right of pit and gallows
The right of pit and gallows is the feudal law granting lords the privilege of inflicting capital punishment on smallfolk if the lord desires, regardless of whatever the accused offence was. The lord has full authority when dealing with his own peasants and servants. After Aegon's Conquest, King Aegon I Targaryen allowed the high lords to retain this right. 
- Fire & Blood, Three Heads Had the Dragon- Governance Under King Aegon I.