Complex sentence: The Pitreavie estate was owned by Lady Christina Bruce, sister of Robert the Bruce, in the 14th century, and by the early 17th century, it was owned by the Kello (or Kellock) family.
Split into simpler sentences: The Pitreavie estate was owned by Lady Christina Bruce, sister of Robert the Bruce, in the 14th century. By the early 17th century, it was owned by the Kello (or Kellock) family.