Complex sentence: In 1503, Margaret came to Scotland; the progress was a grand journey northward, and to this day there exists in the city of York a plaque commemorating the exact spot where the Queen of Scots entered its gates.
Split into simpler sentences: In 1503, Margaret came to Scotland; the progress was a grand journey northward. At York there is a plaque commemorating the exact spot where the Queen of Scots entered its gates.