It can also refer to Peter of Castile.
Peter I (Portuguese: Pedro I ['ped?u] (8 April 1320 – 18 January 1367), called the Just or the Cruel (Portuguese: o Justo, O Cruel), was King of Portugal from 1357 until his death.
He was the third but only surviving son of Afonso IV of Portugal and his wife, Beatrice of Castile.