I have an ongoing discussion with my lecturer about "since" and the past tense. We had a German translation from "A song of ice and fire" and had to translate it back to English.
My translation: "He was a fifty-year-old man and, since he was part of the Guards, had seen many young lords come and go."
My lecturer said "was" (i.e. simple past) is not possible but "since he had been part of the Guards."
(The German text is: "... und seitdem er bei den Wächtern war, hatte er schon viele junge Lords kommen und gehen sehen.")
Is my translation wrong? If both are fine, is there any difference in connotation?
I talked to a friend of mine and she found the usage of "had been" rather strange (native speaker of American English).