Conversation so far:
what was the state of uttar pradesh known as before independence
United Provinces of Agra and Oudh corresponded approximately to the present-day Indian states of Uttar Pradesh and Uttarakhand.
How large was the United Provinces of Agra and Oudh?
According to the District surveys the areas of the two Provinces amounts to 107,494 square miles.
What religion was followed in the United Provinces of Agra and Oudh?
Though the region was overwhelmingly Hindu in population, it was under Muslim rule from the 12th to the 18th cent.

Question: When were the provinces split?
Self-contained rewrite: When was the United Provinces of Agra and Oudh split?