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:
Dominican_Order

Context:
Dominic became the spiritual father to several Albigensian women he had reconciled to the faith, and in 1206 he established them in a convent in Prouille. This convent would become the foundation of the Dominican nuns, thus making the Dominican nuns older than the Dominican friars. Prior Diego sanctioned the building of a monastery for girls whose parents had sent them to the care of the Albigensians because their families were too poor to fulfill their basic needs. The monastery was at Prouille would later become Dominic's headquarters for his missionary effort there. After two years on the mission field, Prior Diego died while traveling back to Spain. When his preaching companions heard of his death, all save Dominic and a very small number of others returned to their homes.

Question:
How long after his mission did Prior Diego die?

two years