- Nobleman with strong Galician and Portuguese connections. Illegitimate son of the Galician nobleman Pedro Fernández de Castro and the Portuguese Aldonça Lourenço de Valadares. He was also brother of Inês de Castro, the fated lover of King Pedro of Portugal.
- Member of the powerful Castro family with several royal connections. Half-brother of Fernando Ruiz de Castro and Juana de Castro, Pedro of Castile's second wife; also half-brother of Inês de Castro, the tragic mistress of Pedro I of Portugal.
- Cousin twice removed of Queen Leonor Teles. [See Isabel de Pina Baleiras, Uma Rainha Inesperada: Leonor Teles (Lisbon: 2013), p.70]
- Settles in Portugal and becomes a trusted member of King Pedro's circle. King Fernando awards him the titles of first Count of Viana (da Foz do Lima), first Count of Arraiolos and first Constable of Portugal. Fernão Lopes says that the title of Count of Arraiolos was bestowed owing to the influence of Queen Leonor Teles.
- In 1354, Pedro I of Castile had ordered his death, as well as that of Álvaro González Morán, but María de Padilla, Pedro's mistress, warned them in time to escape. [Pedro, 16: 104-109]
- In 1366 Álvaro Pérez and Andrés Sánchez de Gres were going to Santiago of Compostela to meet Pedro of Castile, but on hearing that the king had killed the Archbishop of Santiago, they returned to their estates and joined the party of Enrique of Trastámara, recently proclaimed King of Castile. [Pedro, ch. 40: 39-43]
- Governor of Lisbon when Enrique II of Castile invaded Portugal and reached the capital (1373). [Fernando, ch. 74: 6-11]
Alvoro Perez de Castro
Álvaro Peres de Castro
Alvoro Pirez de Castro