Complex sentence: Later, the Burmese army, locally called Maan in Assam became involved in a war with British India as a result of the British Army having driven into Assam and subsequently to Myanmar, then Burma.
Split into simpler sentences: Later, the Burmese army, locally called Maan in Assam became involved in a war with British India. As a result of the British Army had driven into Assam and subsequently to Myanmar, then Burma.