Interpolation (manuscripts)

Interpolation in manuscript traditions is the addition of non-authorial wording to a text after its initial composition. The added material can be a single gloss, a phrase, a verse, or a larger passage. Interpolations arise through marginal notes that migrate into the text, through harmonization across parallels, through doctrinal or ideological expansion, or through deliberate literary revision.

Identifying and evaluating interpolation is a core task of textual criticism in classical, biblical, rabbinic, Islamic, and medieval corpora. The presence or absence of secondary text affects editions, translations, and interpretation, so editors document decisions about probable interpolations with transparent criteria and source-based argumentation.

Works that illustrate the phenomenon range from the gloss at John 5:3b–4 and the longer ending of Mark to the pericope adulterae and the Comma Johanneum, each traced by editors through manuscript distribution and stylistic seams. Beyond the New Testament, scholars debate the expanded Ignatian long recension, stratified layers in the Babylonian Talmud, and cumulative growth in the Mahābhārata, examples that show how interpolation reshapes religious, legal, and literary canons across cultures.