Man with the rosette
The Man with the Rosette was an incarnation of the Master who survived the destruction of Gallifrey. (EDA: The Adventuress of Henrietta Street)
Biography
The Man with the Rosette travelled to Earth in the 18th century and sat with Scarlette in a pub during a brawl and left before the Doctor arrived.
He later met Scarlette at the London docks, where he gave her a pair of rings for the Doctor's wedding. He was later invited to the Doctor's wedding where he did not interact with the guests and sat at the seat reserved for the Doctor's family. (EDA: The Adventuress of Henrietta Street)
Appearance
The Man with the Rosette had dark hair and spoke with an English accent, he was clean shaven to emphasis his contrast to the Doctor who had grown a beard. (EDA: The Adventuress of Henrietta Street)
Behind the scenes
In Lance Parkin's AHistory, Parkin acknowledges that the creater of the character; Lawrence Miles intended the Man with the Rosette to be the Master.