Complex sentence: His son Francis Tresham inherited the estate but within the same year, along with his cousins Catesby and Wintour, became involved in the Gunpowder plot, thus with in a year the estate had a third owner Francis's son Lewis Tresham.
Split into simpler sentences: His son Francis Tresham inherited the estate but within the same year, along with his cousins Catesby and Wintour, became involved in the Gunpowder plot. Thus within a year the estate had a third owner, Francis's son Lewis Tresham.