Sketch elevation of a gate in the Doric order for the 1st Earl of Charlemont at Marino House, County Dublin by leading architect and designer Sir William Chambers (1723-1796). For this sketch design Chambers has used the inside of an envelope. On the verso, below the address, is a broken seal in black wax. Near this are two very faint pencil drawings of scrolls and numerous strokes in black ink from trying out a pen nib, as well as try-outs of a grey wash. Chambers's drawing on the recto also has several such pen strokes and some irregular areas of yellow watercolour. Although this design was not chosen, the overall composition is close to the one built. If Charlemont had rejected the gateway shown in this drawing before Chambers started work on the executed design, then it must date from about or possibly just before 1768. Chambers lived at Berners Street from 1765.

Chambers was born in Sweden and died in London. He travelled widely, visiting China, and studied architecture at the Ecole des Arts, Paris, from 1749 and in Italy from 1750 to 1755. Many of his drawings from this period are contained in his important 'Franco-Italian' album, held in the V&A. Chambers moved to London in 1755 and published his influential Treatise on Civil Architecture in 1759. Chambers demonstrated the breadth of his style in buildings such as Gower (later Carrington) House and Melbourne House, London, in such country houses as Duddingston, Scotland, and in the garden architecture he designed for Wilton House, Wiltshire, and at Kew Gardens. He became head of government building in 1782, and in this capacity built Somerset House, London.