Conversation so far:
What work did Stephen E. Ambrose do in television?
Stephen Ambrose featured in the 1973-74 ITV television series, The World at War, which detailed the history of World War II.
Did Stephen E. Ambrose work as a consultant on any other films besides Saving Private Ryan?
Stephen Ambrose served as a commentator for Lewis & Clark: The Journey of the Corps of Discovery, a documentary by Ken Burns.
What other films did Stephen E. Ambrose work on besides the film Saving Private Ryan and the documentary Lewis & Clark: The Journey of the Corps of Discovery?
Stephen Ambrose served as executive producer for Price for Peace, a documentary concerning the war in the Pacific theater during World War II.
Did Stephen E. Ambrose receive any awards for his work?
Stephen Ambrose won an Emmy as one of the producers for the mini-series Band of Brothers.
What other activities besides writing, television, and film, did Stephen E. Ambrose participate in?
In addition to his academic work and publishing, Stephen Ambrose operated a historical tour business, acting as a tour guide to European locales of World War II.

Question: When did the historical tour business begin?
Self-contained rewrite: When did Stephen E. Ambrose's historical tour business begin?