Lexicometrica 1 L’alignement multicritères des documents médiévaux Hatem Ghorbel, Giovanni Coray École Polytechnique Fédérale de Lausanne, Faculté Informatique et Communications, Laboratoire d’Informatique Théorique, CH 1015 Écublens André Linden, Olivier Collet, Wagih Azzam Université de Genève, Faculté des lettres, Département MELA, 3, rue de Candole, CH 1211 Genève 4 ABSTRACT The aim of text alignment is to establish correspondence relations between subparts of two or more translations or versions of the same document. The majority of the methods in use in the technique of alignment are based on the statistical analysis of word or character frequencies or of string occurrences. In order to improve the efficiency of the process of alignment, other methods have incorporated some structural properties of the documents (e.g. chapters, sections, paragraphs, etc.) as further criteria. When applying the problem of alignment to parallel versions of medieval French manuscripts produced between the XIIth and the XVIth century, classical approaches have shown their limits due to the considerable variation of the appearance and content of these documents. This is basically caused by, (a) the partial evolution of the language, second, (b) the variation of the style (verse and prose) and (c) the various personal interpretations that could come about when rewriting new versions. In this article, we adapt the technique of alignment to parallel versions of ancient texts and we propose a multicriteria approach which takes into account, first the similarities at the lexical, morpho-syntaxic and lexico-semantic levels, and second the similarities of the typographic and rhetorical structure of texts.