As part of a huge restoration project that has been in effect for over 20 years, researchers at Cambridge University have finally restored a 1,000-year-old song back to its former glory.

This truly beautiful piece of music from the Middle Ages is brought back to life in a haunting performance by Sequentia, a three-piece band that specializes in playing music from this era. Send yourself back in time by watching them play in the video below!

It took more than two decades of painstaking work to nail down the instruments and techniques used to play it.

The song, called “Carmina qui quondam,” is just one of many restored peices from an 11th-century manuscript that was stolen from Cambridge and lost for 142 years. It was only by chance that the missing piece (originally written by the philosopher Boethius) was found in a library in Frankfurt, Germany.