formal name of England's contribution to Christendom's seven
most famous churches is The Collegiate Church of Saint Peter
in Westminster, but because it is (and always has been) an
abbey church (whence the word "collegiate" in its formal name), it
is more familiarly known as simply Westminster Abbey. The
earliest documented ecclesiastical structure on its present site
was a church dedicated to St. Peter as part of a Benedictine
monastery (i.e, a "minster") in the first half of the 8th century.
Probably because that monastery or 'minster' lay to the west of
London city at that time, it was informally called 'West Minster'
from its beginning.