D. Pedro was the heir to the throne occupied by his father, King D. Afonso IV. D. Inês was a gallician lady, the bastard daughter of Pedro Fernandez de Castro, one of the most powerful men in Spain who was, like D. Pedro, the grandson of Sancho IV, King of Castile, which made D. Pedro and D. Inês cousins. D. Constança, wife of D. Pedro and future Queen of Portugal was also a cousin of D. Inês's.
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