Conversation so far:
What were Daniel Boone's businesses?
he kept a tavern and worked as a surveyor, horse trader, and land speculator.
Was  he successful?
He was initially prosperous, owning seven slaves by 1787, a relatively large number for Kentucky at the time.
what happened to change his prosperity?
Boone the trailblazer was too unsophisticated for the civilization which followed him and which eventually defrauded him of his land.
what did he do after this happened?
Frustrated with the legal hassles that went with land speculation, in 1788, Boone moved upriver to Point Pleasant, Virginia .
What did he do there?
he operated a trading post and occasionally worked as a surveyor's assistant.
Did he take a more permanent position anywhere?
When Virginia created Kanawha County in 1789, Boone was appointed lieutenant colonel of the county militia.

Question: How long was he lieutenant colonel?
Self-contained rewrite: How long was Daniel Boone lieutenant colonel?