text: The kingdom of Castile ( Castilla ) built a global empire , spreading its culture and language in the Americas and biologically and culturally mixing with the Indigenous peoples and ultimately , the African slaves , altering the composition of the hemisphere .
simplified: The kingdom of Castile ( Castilla ) built a global empire , spreading their culture and language in the Americas and biologically and culturally mixing with the indigenous peoples , altering the composition of the hemisphere .