Why was Sybil killed off on Downton Abbey and what happened to Tom after she died?

Even all these years later many of us might still be wondering why Sybil was killed off on Downton Abbey and what happened to her husband Tom Branson in the show and films.

The original Downton Abbey series took the world by storm with its tales of upstairs downstairs life at the fictional Crawley family’s Yorkshire estate. Spanning 1912-1926, romance was key to Downton Abbey from season 1 to 6 and fans were gripped by the will-they-won’t-they romance between Lady Mary and Matthew only to be devastated when he perished in a car crash. But theirs wasn’t the only love story that captivated us and what happened to Lady Sybil was every bit as tragic.