Answered in example sentence
"I have been under a mistake all this time," answered Don Quixote, "for in truth I thought it was a castle, and not a bad one; but since it appears that it is not a castle but an inn, all that can be done now is that you should excuse the payment, for I cannot contravene the rule of knights-errant, of whom I know as a fact (and up to the present I have read nothing to the contrary) that they never paid for lodging or anything else in the inn where they might be; for any hospitality that might be offered them is their due by law and right in return for the insufferable toil they endure in seeking adventures by night and by day, in summer and in winter, on foot and on horseback, in hunger and thirst, cold and heat, exposed to all the inclemencies of heaven and all the hardships of earth."