On the latter occasion Castro's octavas were awarded the first prize.
Lope de Vega dedicated to him a celebrated play entitled Las Almenas de Toro (1619), and when Castro's Comedias were published in 1618-1621 he dedicated the first volume to Lope de Vega's daughter.
The drama that has made Castro's reputation is Las Mocedades del Cid (1 599 ?), to the first part of which Corneille was largely indebted for the materials of his tragedy.
Castro's Fuerza de la costumbre is the source of Love's Care, a play ascribed to Fletcher.