Archival groups are aggregates of items that share a common provenance. Archival groups may range in size from several thousand items (e.g., the entire body of drawings, models, and written documents from an architect's office) to just a few items (e.g., a handful of surviving drawings from one architectural project). Group-level cataloging focuses on the description of coherent, collective bodies of works. The description emphasizes the characteristics of the group as a whole, and highlights the unique and distinctive characteristics of the most important works in the group. Groups are usually defined by repositories, and may have several subgroups that are established by archival principles of provenance. The catalog record for a group normally corresponds to a physical group as it currently exists and is stored by the repository; however, historical groups may also be described. Groups may be divided into subgroups.