Complex sentence: In 1911, Mongolia declared its independence from the Qing dynasty after over two centuries of foreign rule, but independence under the Bogd Khan did not last since it was not recognized by its two neighbors (Russia and China) and was considered autonomous under Chinese rule.
Split into simpler sentences: In 1911, Mongolia declared its independence from the Qing dynasty after over two centuries of foreign rule. Independence under the Bogd Khan did not last, since it was not recognized by its two neighbors (Russia and China) and was considered autonomous under Chinese rule.