generate questions: With the union of the crowns of Castille and Aragon (1479), the use of Spanish gradually became more prestigious. Starting in the 16th century, Catalan literature experienced a decline, the language came under the influence of Spanish, and the urban and literary classes became bilingual.
When were Castille and Aragon united? {sep_token} After 1479, what language became more valued? {sep_token} When did Catalan literature begin a downward trend? {sep_token} What language began to supersede Catalan? {sep_token} At this time what classes became bilingual? {sep_token}