Afonso IV of Portugal
Considering Denis an "Infante of Portugal" is a debatable subject. Some historians consider him a natural son of Peter I, so the title Infante of Portugal could never be attributed to him. Other opinions refer that after the death of Inês de Castro, ordered by Pedro's father King Afonso IV of Portugal, the Prince after inheriting the throne admitted that he had married Inês secretly, and because of that she was a lawful Queen of Portugal.