 Some of the deaf sons were in line to inherit the family’s properties, and literacy was a requirement for legal recognition as an heir.The modern recorded history of sign language began in the 17th century in Spain, in part with Bonet.In 1620, Juan Pablo Bonet published "Reducción de las letras y arte para enseñar a hablar a los mudos" ("Summary of the letters and the art of teaching speech to the mute") in Madrid.