Complex sentence: He spent his last years rebuilding Toungoo and war ravaged regions around his kingdom but also saw his kingdom increasingly squeezed by the Portuguese in the south and Ava (Inwa) in the north.
Split into simpler sentences: He spent his last years rebuilding the city of Toungoo and other war ravaged regions around his kingdom. But he also saw his kingdom increasingly boxed in by the Portuguese from the south and Ava (Inwa) from the north.