The internal reinforcement method (IRM) was developed by Fernando Lizzi in the early 1950s. It is a complete structural system reinforcement method used to retrofit nonreinforced masonry and stone structures and any associated foundation systems. The general design principles of the foundation retrofit are similar to the principles used in the structure retrofit, for placement and engagement of reinforcement. The IRM technology integrates the complete structure, the foundation and bridge or building, into a continuously reinforced seismic-resistant system. The Three Arches Bridge is the only three-span bridge in Venice today. Built in the 17th century, this simple pedestrian bridge was constructed of nonreinforced clay brick masonry with spread footings bearing on the canal floor. Over time, the differential settlement caused localized distress to the overall structure. It was in such a state of disrepair that it was scheduled for demolition in the early 1960s. Lizzi was named to design and construct the historic preservation and structural retrofit of the complete structure. This was accomplished with reticulated internal structural stitching and reticulated micropiles. This structure is a case study of use of the IRM for static and seismic retrofit. The geometric simplicity of the bridge and the clarity of purpose and execution of the reticulated internal stitching and micropiles provide an example of technology that exemplifies the IRM method of integrated complete system static and seismic retrofit.