 The church 's appearance in the mid @-@ 16th century , shortly before its completion , is known from a woodcut by Girolamo Franzini . Its facade appears almost square ; at its center there was a portal with a tympanum , surmounted by a large fanlight opened by a round window . On its side were three rows of pilasters with two pairs of niches , one over the other . A bell @-@ gable was on one side of the roof . 
