Complex sentence: Sir James Sandilands of Calder, a friend of the Protestant reformer, John Knox, was also preceptor of the powerful religious and military Order of the Knights of St John, whose headquarters were at the Priory of Torphichen in West Lothian.
Split into simpler sentences: Sir James Sandilands of Calder was a friend of the Protestant reformer, John Knox. He was also preceptor of the powerful religious and military Order of the Knights of St John, whose headquarters were at the Priory of Torphichen in West Lothian.