Question: Who is the paternal grandfather of Thomas Of Lancaster, 1St Duke Of Clarence?
Sentence (from "Thomas of Lancaster, 1st Duke of Clarence"): Thomas of Lancaster, 1st Duke of Clarence (autumn 1387 – 22 March 1421) was a medieval English prince and soldier, the second son of King Henry IV of England, brother of Henry V, and heir to the throne in the event of his brother's death.
Relevant evidence: Yes