The Romanesque portal was built in 1240 by the maestro Radovan. It represents one of the most important and complete Medieval cycles of sculpture in the Adriatic region to have survived to this day and it is considered the most important monument of Romanesque sculpture in the Dalmatian region. The narthex, dating back to the Gothic period, acts as the main entrance to Saint Lawrence’s Cathedral and leads to the baptistery. The vaults and walls of the narthex presented areas washed away by water alternated with areas covered in layers of newly formed limestone. Under the considerable layer of calcite that concealed the capitals, some delicate reliefs had fragmented. The grouting were in a bad state of conservation and many of the joints had been badly plastered with grey cement. Furthermore, large quantities of bird droppings had accumulated on the capitals and on the portal pediment. The entire portal was covered in a thin brown patina. Close examination under the microscope verified the absence of polychromy. The stone had cracked in various points due to tensions caused by the oxidised iron hinges and staples swelling. Once the layers of bird nests, droppings and surface layers of dust had been removed, the most suitable cleaning methods for each situation were chosen. The entire baptistery was carefully washed with water and soft brushes, avoiding the more fragile and disintegrated zones lacking dust deposits. The surfaces in grey marble were treated with various coats of microcrystalline wax.
The restoration is dedicated to the memory of Maria Teresa Gaja Rubin de Cervin Albrizzi.