You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Catalan_language

Context:
With the Treaty of the Pyrenees (1659), Spain ceded the northern part of Catalonia to France, and soon thereafter the local Catalan varieties came under the influence of French, which in 1700 became the sole official language of the region.

Question:
When did French become the official language of that part of Catalonia?

1700