in Roman history, memoranda and notes that were later used by historians as source materials. Originally, commentarii were simply informal personal notes written by people to assist their memory in regard to personal, household, or public business. The typical Roman household, for instance, kept a diary and account book, while men in public life kept notebooks for speeches, legal cases, and items of general business. The first official use of commentarii developed in the priestly colleges, which used such notes to list the details of religious ceremonies and rituals. Magistrates too had their regular notes on procedural aspects, which they would hand on to successors in order to maintain the routine of their offices. Provincial governors also kept commentarii, which they consulted when writing their reports to the Senate
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