18 This is the vexed question of ‘interpolation’, or the extent to which the texts in the Digest represent classical law, or post-classical rewriting during the process of compilation of Justinian's Corpus Iuris Civilis. The pendulum has swung back and forth on this issue, but generally today it is felt that while changes to wording are numerous, changes to substance are probably less so, although this should not lead to the uncritical acceptance of all texts: see Johnston (n. 15) 14-22; Watson, A., ‘Prolegomena to Establishing Pre-Justinianic Texts’, TR 62 (1994) 113–25Google Scholar. Kaser, M., Zur Methodologie der römischen Rechtsquellenforschung (Vienna 1972)Google Scholar; Johnston, D., ‘Justinian's Digest. The Interpretation of Interpolation’, Oxford Journal of Legal Studies 9 (1989) 149–66CrossRefGoogle Scholar. We will make frequent reference to pre-Justinianic texts to help control for interpolations. On pre-Justinianic texts, see Johnston, , Roman Law (n. 15) 12–14Google Scholar.