Complex sentence: Taras Shevchenko spent the last years of his life working on new poetry, paintings, and engravings, as well as editing his older works, but after his difficult years in exile his final illness proved too much.
Split into simpler sentences: Taras Shevchenko spent the last years of his life working on new poetry, paintings, and engravings, as well as editing his older works. But after his difficult years in exile his final illness proved too much.