Godwin Gretsith.

The names of three master freemasons are recorded in connection with the building of Westminster Abbey. The Abbey was built in the style of the Norman Romanesque and positioned just to the east of the existing church. Those master freemasons responsible for the construction of the Abbey were Godwin Gretsith, Teinfrith and Leofsi Duddeson. Freemasons were a select guild of masons that specialized in the building of churches. The term 'free' refers to their status of being exempted from the laws that were imposed upon the common craftsmen.

See - Stone Masonry
         Freemasonry