It is likely the Thomas in question is the son of the 3rd Earl Rivers, or a family relation.
Sir Thomas died in 1635 to be succeeded by his son, John, who four years later inherited the title of Earl Rivers.
The estate was sold to Richard Savage, 4th Earl Rivers, in 1708.
In 1694 he succeeded his father as 4th Earl Rivers.
It was superseded when he inherited his father's title and became the second Earl Rivers.
For more information on this creation, see Earl Rivers.
Richard Woodville was the last of his family to hold the title of Earl Rivers.
Why, he asked himself, had his uncle, Earl Rivers, been placed under arrest?
Later, Earl Rivers and his son John were also apprehended and murdered.
The prince had to go straight to London to take the throne, and his uncle, Earl Rivers, went with him.