How long did it take to build Edinburgh Castle?

The building of Edinburgh Castle took several centuries. The castle was originally built in the 12th century by King David I, and it was subsequently expanded and renovated over the course of the next few centuries. The final major addition to the castle was the Half Moon Battery, which was completed in the late 16th century. The castle took around 400 years to build, starting with David's original fortifications in the 12th century and ending with the completion of the Half Moon Battery in 1588.