In an introductory note (volume 1, folio iv.), Martyn states that many of the arms were unpublished, and taken from seals, drawings, paintings and manuscript blazons; also from a manuscript collection of heraldry `purchased at Mr Cummyngs sale by a Mr Rose`. This probably refers to James Cummyng, herald painter and Lyon Clerk Depute (died 1793). Martyn sometimes gives the source for a particular coat of arms, and occasionally criticises the heraldry.