Episode #1.1 - S1-E1
Continuity mistake: Near the end of the first episode, when Robert Crawley gets into bed he first puts his candlestick down on the nightstand. Then it disappears. Then when he's in bed and ready to blow out the candle, it's suddenly back again.
Answer: Lord Sinderby purchased the house, furnished and appointed, from someone else, complete with staff that come with the home (some of whom aren't happy to be working for a Jewish family). He bought the title, as well. If the artwork featuring Jesus is valuable, he might keep it. Also interesting, his ancestors Anglicized their name, though he is proudly Jewish.
Michael Albert