The various surviving disc and composite brooches provide proof of the skill and craftsmanship of Anglo-Saxon metalsmiths. Surprisingly, no one has conducted a full geometrical analysis of these brooches to discover the design process preceding the casting and decoration. This thesis endeavors to rectify this through a geometrical investigation of the sophisticated geometrical planning principles used by Anglo-Saxon craftsmen in the creation of these elaborate brooches. Through the use of simple geometrical constructions, smiths were able to create works of great beauty and sophistication. Closer inspection reveals that Anglo-Saxon smiths produced all the composite disc brooches in this study using similar processes of planning. In order to plan out the compositions of each brooch, master smiths would only need a compass, a straightedge, and some material on which to write. Each brooch reveals the same kind of coherent geometry, sharing traits and patterns; with proportions tend to be governed by a series of modular association.
Although the master smiths or designers of the composite brooches used simple tools to create the composition, the figures in this thesis were created using the Vectorworks CAD program. This significantly expedited the analytical process and allowed for exact measurements. Despite using the computer program to replicate the planning process, all the figures can be recreated with just a compass and straightedge. While a complete geometric study of all the composite disc brooches needs to be done, this study examines five of the best preserved and well-crafted of that type, ranging from some of the simplest to the most elaborate, as an introduction to the subject.