Standing as one of Ireland’s finest and most complete round towers, the Rattoo tower represents a masterpiece of medieval ecclesiastical architecture with unique decorative features found nowhere else in the country. Rising to approximately 29.56 meters, this exceptional structure combines architectural sophistication with rare carved elements that make it invaluable for understanding Irish medieval art.

Outstanding Construction and Materials

Built from dressed and evenly coursed yellow sandstone—described as hard quartzose sandstone—the tower demonstrates exceptional craftsmanship both internally and externally. The structure stands on a limestone plinth beneath an offset, with the tower evenly battered (tapering) from a 20-centimeter-wide offset at the base to a cornice just below the cap. This creates a pleasing visual effect where the tower’s 15-meter base circumference reduces to 3.5 meters diameter at the top window level—a reduction in radius of 55 centimeters over 21.44 meters, giving a precise batter of 1.39 degrees.

Sophisticated Interior Organisation

The tower originally contained five stories above the basement, with floor heights measuring 6.1m, 4.2m, 3.4m, 4.2m, and a top story of 3.1m to the cornice plus 2.8m to the internal vertex. Between each floor, rough corbel stones project from the walls to support wooden flooring, though there is no access to these levels today. The internal diameter measures 2.3 meters at the doorway, where walls are just over 1 meter thick.

Unique Decorative Doorway

The round-headed doorway, positioned 2.83 meters above ground level on the southeast side, features decoration that appears to be unique among Irish round towers. The 1.6-meter-high entrance consists of a semi-circular arch of three stones ornamented with a simple curvilinear motif in relief, carved about 1 centimeter thick though much weathered by centuries of exposure.

The central portion above the keystone displays upturned curving spirals at each end, measuring 4.5 centimeters in diameter, with the overall central motif measuring 20 centimeters across. From underneath each spiral extends a plain bead molding that rounds the arch for 44 centimeters before terminating in curving spirals on either side. Remarkably, the spirals on either side of the arch extend in opposite directions—clockwise on the left and anti-clockwise on the right—creating a balanced but asymmetrical design that appears nowhere else in Irish round tower architecture.

The Unique Sheela-na-gig

Perhaps most extraordinarily, Rattoo contains Ireland’s only known Sheela-na-gig carved within a round tower. This remarkable figure was discovered in 1880-81 when the Office of Public Works reset the top two-thirds of the conical cap. Located on the top left-hand corner of the frame of the north window and facing into the tower’s interior, the carving is executed in relief across two stones—the head and shoulders on the lintel stone, with the rest of the figure on the jamb stone below.

Measuring 30 centimeters from head to foot and 14 centimeters at the widest point across the knees, this unique example of medieval Irish erotic sculpture within an ecclesiastical context raises fascinating questions about medieval attitudes and the integration of seemingly contradictory symbolic systems. A plaster cast of this rare artifact is preserved in the National Museum of Ireland.

19th-Century Restoration and Historical Context

The tower underwent significant restoration in 1880-81 by the Commissioners of Public Works, who replaced the top two-thirds of the conical cap. This restoration preserved the tower’s complete appearance while maintaining its structural integrity.

Historical accounts from 1832 describe the tower standing on a circular earthen terrace with a causeway running eastward from below the doorway for approximately 38.7 meters. This causeway disappeared around 1880 when Wilson Gunn of nearby Rattoo House drained and planted the surrounding land, though aerial photography can still discern traces of this medieval landscape feature.

Window Arrangement

The tower’s fenestration includes four windows at the top level facing slightly to the right of the cardinal points, each measuring 1.45 meters to the apex and tapering from 51 centimeters wide at the base to 43 centimeters at the springing. The only other window sits on the fourth floor, measuring 76 centimeters to the apex and tapering from 43 centimeters at the base to 33 centimeters at the springing.