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:
Iranian_languages

Context:
What is known in Iranian linguistic history as the "Middle Iranian" era is thought to begin around the 4th century BCE lasting through the 9th century. Linguistically the Middle Iranian languages are conventionally classified into two main groups, Western and Eastern.

Question:
What are the two main divisions of Middle Iranian?

Western and Eastern