Margaret "Peggy" Thompson, later Margaret Neilson, was the housekeeper at Coilsfield House or Montgomery Castle in Ayrshire, Scotland. She married John Neilsen of Monyfee. The couple lived at Minnybae Farm near Kirkoswald. She was the 'charming Fillette' of Robert Burns fame and her husband was an old acquaintance of the poet. It was on 23 August 1775 that she was first seen in her garden by Burns when he was out at noon in the school's backyard measuring the altitude of the sun. Peggy in later life moved to Ayr where her children still lived in 1840.