In Seven Lamps, Ruskin defined architecture as ornament. He declared architecture as the addition of "certain characters venerable or beautiful, but otherwise unnecessary". He argued that to determine the "height of a breastwork or the position of a bastion" was not architectural. Samuel Higgins, one of the well-known commentators on Ruskin, defined architecture as the "art of the beautiful manifested in structure". Other twentieth-century scholars have argued that these views are not entirely accurate or fair. John Unrau points out that Ruskin's drawing of the interior of Basilica of San Frediano, Lucca, portrayed an acute experience of architectural space and interior. Ruskin's drawing of the interior of the loggia of the Ducal Palace captured the spatial qualities of a semi-open space. One reason can be the emerging Victorian architectural aesthetics of massiveness and substantiality. It is also possible that Ruskin's interest in surface was connected to his (over) familiarity with the visual language of Venetian buildings.