 In the transepts of Notre-Dame, the wall above the triforium gallery is pierced with rose windows.In later Gothic churches, the vertical members in the tracery of galleries and clerestory may merge into a single decorative unit where the stages are present but not clearly defined, as at Saint-Ouen at Rouen and the choir of Gloucester Cathedral in England.In the major Gothic churches of Italy, triforium galleries are most often found in churches influenced by the architecture of Normandy, and were used at abbeys of women, as a space for the nuns to attend services.