  The paper introduces a knowledge representation language that combines the
event calculus with description logic in a logic programming framework. The
purpose is to provide the user with an expressive language for modelling and
analysing systems that evolve over time. The approach is exemplified with the
logic programming language as implemented in the Fusemate system. The paper
extends Fusemate's rule language with a weakly DL-safe interface to the
description logic $\cal ALCIF$ and adapts the event calculus to this extended
language. This way, time-stamped ABoxes can be manipulated as fluents in the
event calculus. All that is done in the frame of Fusemate's concept of
stratification by time. The paper provides conditions for soundness and
completeness where appropriate. Using an elaborated example it demonstrates the
interplay of the event calculus, description logic and logic programming rules
for computing possible models as plausible explanations of the current state of
the modelled system.
