Context: 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.

Question: When were Castille and Aragon united?
Answer: 1479

Question: After 1479, what language became more valued?
Answer: Spanish

Question: When did Catalan literature begin a downward trend?
Answer: 16th century

Question: What language began to supersede Catalan?
Answer: Spanish

Question: At this time what classes became bilingual?
Answer: urban and literary