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:
Russian_Soviet_Federative_Socialist_Republic

Context:
The RSFSR was established on November 7, 1917 (October Revolution) as a sovereign state. The first Constitution was adopted in 1918. In 1922 the Russian SFSR signed the Treaty on the Creation of the USSR.

Question:
What event led to the establishment of the RSFSR?

October Revolution