It was one of five canons in classical rhetoric (the others being inventio, dispositio, elocutio, and pronuntiatio) concerned with the crafting and delivery of speeches and prose.
For example, as part of dispositio, some attention was paid to creating structures (such as the divisio, an outline of the major arguments of a discourse) that would also aid memory.
Rather, the orator also had to have at his command a wide body of knowledge to permit improvisation, to respond to questions, and to refute opposing arguments.
When the Humanists took up the ideas on memory found the writings of Classical authors, memoria played an important role in the pedagogical system.
Children's ability to memorize was aided by "memory tables", which were first available in manuscript form, and were, from the 1470s onwards, some of the first products of the printing press.
The ad Herennium states that memory is the "treasury of things invented", indirectly referring to the custom of accumulating commonplaces.
Hence, for a rhetor, memory is as much related to the need to extemporize as to the necessity to memorize a discourse for delivery; in this way it is linked to kairos and to the ideas of copia and amplification (Burton).
[4] Unlike ancient Greece, in today's society, it is much more acceptable for politicians and for people of authority to use aids when delivering addresses.
[5] Although it could be viewed as an aid to use notes or teleprompters, greater importance is placed on actually conveying the information to the audience in a clear and concise manner.