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. Indeterminacy of the duration value can be expressed by assigning a numerical interval to the property P90 has value of E54 Dimension.
The time span of the Battle of Issos 333 B.C.E. (E52) had duration Battle of Issos duration (E54). (Howard, 2012)