Breakdown of El mercader vio a un bandido detrás del camello.
un
a, an (masculine)
ver
to see / to look / appear
del
from the / of the
detrás
behind
Questions & Answers about El mercader vio a un bandido detrás del camello.
Why is there a personal a before un bandido? I thought it was only for specific, known people.
The personal a is used for any specific, real person who is the direct object of a verb, even if they are unidentified to the speaker or introduced with an indefinite article. Since the merchant actually saw a physical person standing there, the bandit is "real" in the context of the sentence, so the a is required. You generally only drop the a with an indefinite person when their existence is theoretical (e.g., Busco un médico - "I am looking for a doctor").
Could I use atrás del or tras el instead of detrás del here?
You can definitely use tras el camello; it means the exact same thing, though tras can sound a bit more literary or formal. Atrás, however, is traditionally an adverb of direction or location that stands alone (like "He stayed behind" = Se quedó atrás). While you will often hear atrás de in colloquial Latin American Spanish, standard grammar prefers detrás de when followed by a specific reference object.
Is mercader a common everyday word for someone who sells things?
Not in modern, everyday Spanish. For a modern-day shopkeeper, businessperson, or merchant, you would use comerciante or vendedor. Mercader is an older word that gives the sentence a historical or storybook feel, much like how the English word "merchant" often appears in fairy tales, fantasy novels, or historical contexts.