Compound brick vaults by slices in written sources

The vaults called "par tranches" by Auguste Choisy are those built by laying the bricks with their bed in a vertical or slightly sloped position. The form and process of executing these vaults have been scarcely studied, partly because it is difficult to define the hidden elements of the masonry. Until the 19th century there were no primary sources explaining these ways of building, which depend more on the skill of the masons than on the abstract knowledge of the designer. This article compares the technical proposals of French and Spanish texts from the late 19th century addressing construction works in Byzantium and Extremadura (Spain). The genesis of the system (designed for barrel vaults) is explained according to each author. The subsequent evolution of different types of compound vaults is analysed with special attention to the groin vault since the others are based on its layout and construction strategies.