This paper presents the analysis of the structure of Mallorca Cathedral taking into account the influence on structural behaviour of auxiliary iron ties used during the construction process. Recent studies (Roca et al., 2012, 2013) have presented some hypotheses about the construction process of the cathedral. The present study complements the previous results by considering the use of auxiliary ties as temporary stabilizing device during the construction. Evidence of the use of ties during the construction has been recognized after a comprehensive survey. The study of the role of such ties and the effect of their later removal are studied by a FE analysis carried out on a representative bay of the structure. The study includes a time-dependent FE analysis after the removal of the ties to assess the long-term structural behaviour. The results of the numerical analysis are compared with the deformation trends identified by means of a recent monitoring campaign.