Complex sentence: They divorced three years before he died and was excluded from the Will-before he died, Brett even went so far as creating a false wall in his studio, behind which he kept a number of paintings so Wendy could not seize them.
Split into simpler sentences: They divorced three years before he died and was excluded from the Will. Before he died, Brett even went so far as creating a false wall in his studio, behind which he kept a number of paintings so Wendy could not seize them.