Charles II criticised Bruce's initial plans for the internal layout, and an improved scheme was eventually approved. Construction began in July 1671, and by 1674 much of the work was complete. Bruce built a second gothic tower to mirror the existing one built by James V between 1528 and 1532, and created the courtyard block in a restrained classical style. A second phase of work started in 1676, when the Duke of Lauderdale ordered Bruce to demolish and rebuild the main west façade, resulting by 1679 in the screen wall, topped by a carved imperial crown, which forms the main entrance.