The political economy of conflict: greed versus grievance argument

Have all conflicts a primarily material basis?

Part of scene 52 of the Bayeux Tapestry. This depicts mounted Normans attacking the Anglo-Saxon infantry.
11th century unknown — Lucien Musset, “The Bayeux Tapestry”, 2005, Boydell Press, ISBN 1–84383–163–5, p. 237