This property describes the length of time covered by an instance of E52 Time-Span. It allows an instance of E52 Time-Span to be associated with an instance of E54 Dimension representing duration independent from the actual beginning and end. Indeterminacyof the duration value can be expressed by assigning a numerical interval to the property P90 has valueof E54 Dimension.
the time span of the Battle of Issos 333 B.C.E. (E52) had durationBattle of Issos duration (E54) (Howard, 2012)