Katherine Stuart

Katherine used a visit to London, ostensibly to deal with her husband's estate, to clandestinely pass messages to Royalists in the city. After her discovery she was imprisoned in the Tower of London before being released by the intervention of the French ambassador.
Widowed since 1642, Katherine married James Livingston in 1648. The pair unsuccessfully attempted to release the king from parliament's captivity during his journey to trial. After the king's execution, the couple fled to the Netherlands where Katherine died in 1650. Provided by Wikipedia