This is the PAPERBACK version. Published for the author's family, the book traces the lineage of John of Gaunt, Duke of Lancaster, through his eldest daughter Philippa, Queen of Portugal, to the Lancaster family in Portugal and, in particular, to the current head of the family. The book includes a short summary of the dukedom of Lancaster and the medieval relationships between England and Portugal, where John of Gaunt was fundamental, which consolidated an alliance that has endured to the present day.