The identification of these three stars as a belt is a very old one. The Arabic names of two of the
stars reflect this: Mintaka means 'the belt' and
Alnitak means 'the girdle'. (The name of the third
star, Alnilam, means 'the string of pearls'.)
It has been suggested that the three Belt-stars influenced the placing of the Pyramids at Giza,
and it is certainly true that there is a remarkable correspondence of position between the Pyramids and the stars.
Alnilam is the most massive and luminous of the three
stars, so that despite its greater distance it still shines more brightly
than its two companions. If the three stars were the same distance away,
Alnilam would easily outshine the other Belt-stars. It is about
10,000 times more luminous than the Sun.