St Peter's Release From Prison, in the Caligula Troper

Made up of fragments from a late Anglo-Saxon liturgical chant book, the Caligula Troper's illuminations introduce songs which would be inserted into the mass on special feast days and sung by a soloist, hence the book's small scale. The pictures' geometric abstraction of form and use of vibrant colours embellished with gold give an opulence that speaks of manufacture for use by an important figure. It is named for its 17th-century position in a bookcase supporting a bust of Caligula in the Cotton rare books library. Its selection of tropes (songs) and where it was in the Middle Ages suggest origins at Winchester or Worcester.An unusual triple-scene page tells the dramatic narrative of Peter's release from prison. First the angel (top right) awakens him ('Arise quickly,' on the scroll in Latin). Next, Peter's thanks mark his freedom. Lastly, as the city gate opens and the angel departs, Peter realises what has happened. His words from Acts 12:11 also begin the introit antiphon (opening chant) for his feast and are echoed in the surrounding poem.