Grimnir

Queen Grimnir the Impaler ruled Lancre between 1514 and 1553, 1553 and 1557, 1557 and 1562, 1562 to 1567, and finally (insofar as anything involving vampires is ever final) between 1568 and 1573.

Possibly a take on Roundworld "vampire" countess Elisabeth Bathory, who was infamous in Hungary in the 1600's.