The bonding of the brickwork is characteristic of a late medieval date. Irregular shaped bricks are laid in a fairly thick mortar and in a haphazard bond consisting largely of rows of stretchers with the occasional header used to bond the two wall surfaces together. This construction pre-dated the widespread adoption of English Bond (alternating courses of headers and stretchers) and Flemish Bond (alternating headers and stretchers in each course) in England. The courses of brickwork are bonded together with a lime-based 'common mortar' which was originally pointed back flush with the wall face. It survives on the bedding planes and is exposed in several places on the north elevation. Guildhall collection Works of art include a portrait, painted by Thomas Phillips, of Sir Joseph Banks, recorder of Boston in 1813, who sailed with Captain James Cook aboard the Endeavour on the first great voyage to discover Australia. The guildhall also holds a copy of Foxe's Book of Martyrs and artefacts from various archaeological excavations. See also Guild Guildhall Museum References External links Boston Guildhall – official site Guildhall Boston, Lincolnshire Museums in Lincolnshire History museums in Lincolnshire Grade I listed buildings in Lincolnshire Local museums in Lincolnshire Buildings and structures in Boston, Lincolnshire