I posted a question several days ago about the significance of using “a,” in the sentence of Jeffery Archer’s novel, “False Impression” - “General Harry Wentworth was commanding his left flank when a defeated Napoleon rode off the battle field and into exile.
Most of answers from you were “a”, not “the” was used to reflect one of various aspects of Napoleon’s character, which I think I was sold.
With that said, what is the role of a in the following sentence that appears in the subsequent chapter (P.59):
"When a Mr. Andrews, the butler at the Wentworth Hall, had rung the previous day to say that painting would be ready for collection in the morning, Ruth had scheduled one of her high-security air ride trucks to be at the hall by eight o’clock."
Is a necessary before Mr. Andrews in the above sentence? Or does it imply Andrews the butler is a member of the Andrews family known for serving the distinguished family of Earl of Wentworth for generations?
I’m asking this as I’m occupied with the significance and functions of article, because it is always a persistent headache for an English learner of a country devoid of the habit of using the article.