Introduction

The conservation of historical buildings has always depended on reliable and efficient procedures and technologies. Moreover, in the early modern period as still today, constraints on the space available for the assembly and operation of maintenance scaffolding typically entailed considerable construction challenges. A significant inventory of methods, techniques and spaces for architectural restoration was developed by the fruitful laboratory of St. Peter's Fabbrica in the Vatican, the papal institution in charge since 1506 for the construction and maintenance of the principal Basilica of Christianity. The Fabbrica was one of the most influential authorities on building practice in the modern era. Its extraordinary efficiency in the organization of manpower and its influence on the improvement of building techniques was not solely the product of its administrative structure or its employment of the period's best practitioners. The technical and organizational excellence of the Vatican Fabbrica were also connected to the development of construction and restoration scaffolding, and the working spaces to which they related.

Since its initial sixteenth-century reconstruction, the Vatican Basilica's architectural space imposed severe restrictions on the design and functionality of restoration scaffoldings. Not only did these structures have to rise great heights and accommodate large numbers of practitioners, but they also had to be assembled and used without interfering with liturgical ceremonies. The innovative mobile scaffoldings developed in the first half of the eighteenth century by the illiterate St. Peter's carpenter Nicola Zabaglia (1667-1750) met these demands.