Manchester started out as a small medieval parish in 1421 and continued to grow and expand its borders. In 1847, it was a big, bustling city, and it achieved cathedral status with the creation of a new diocese. The cathedral's nave, the widest of its kind in Britain, is formed by six bays, as is the choir. The choir stalls are beautifully carved and date from the early 16th century. The carvings depict a humorous interpretation of life in the Middle Ages. The choir screen is a woodcarving from the same era. Central to the 19th-century grass-roots movement that helped abolish slavery throughout the British Empire, and frequently associated with the kinds of socialist free thinking for which Manchester itself is identified, it's one of the most resilient religious buildings in Britain, having survived vandals during the 17th-century civil wars, a direct hit by a Nazi firebomb in 1941, and damage from an IRA bombing in 1996. Of special note is the "Fire Window," a replacement for a window destroyed during World War II, whose colors evoke the infernos of the Nazi Blitz.