Abstract This paper describes the evolution and use of key concepts in the CRM family of standards to document the relationship between the objects and events documented and time. It discusses the differences between phenomenological and declarative time and between absolute and relative dating and how they are implemented in the CRM. It considers the use of periods, spacetime volumes, and the concept of a presence, and finally explores the registration of dates. It is intended as an introduction to the richness of the ontological toolset contained in the CRM and its application to recording time.