Justinian's Codex Book 8
title 4 lex 1 (Title: Unde
vi, Recte possidenti)
Emperors Diocletian and Maximian, and the Caesars, to Theodorus.
A person lawfully in possession has the right to use a controlled amount of blameless (justified) force (resistance) [moderamen inculpatae tutelae] to repel any violence exerted for the purpose of depriving him of possession, if he holds the property without defect.
Stuttgart, Württembergische Landesbibliothek
jur. 71, fol. 152vb
Glossa interlinea: "Hec enim vicia intelliguntur: id est non vi, non clam; idest moderata pãique (?) tuitione."