Schematic plan of the whole crossing with a superimposed plan of the drum and peristyle

WRE/5/2/5

c.1693–94

Sir Christopher (1632–1723) Wren, Nicholas (c.1662–1736) Hawksmoor

Pen and brown ink over pencil, with pencil and black chalk additions. Smooth laid paper, horizontal fold. 58.1 x 50.6 cm. Watermark: Strasbourg lily WR; countermark: PVL combined.

An overlay of the plan of the lower drum and peristyle of a 32-bay dome on a plan of the crossing square which, for convenience, repeats the same quarter-plan four times. Drawn probably by Hawksmoor but with some pencil by Wren. Datable c.1693-94. Drawn scale, just under 10 ft to 1 inch (10 ft = 27 mm). The plan of the dome is in dotted ink outlines, to distinguish it from the crossing square. Wider-spaced dots mark the radial centres of the 32 bays. Pencil under-drawing describes the geometry of the dome and crossing space: the octagon of the dome at church-floor level is defined by the fronts of the crossing arches and the circle of its drum by the front faces of the pilasters of the peristyle. Octagon and circle coincide at the centres of the eight crossing arches of the dome where the dome is 108 ft in diameter. The crossing arches are 26 ft deep. These should produce a 160-ft crossing square but the plan scales about 2 ft longer on the north-south than the east-west axis and this distorts the relationship between the outer circumference of the drum and the inner diagonal faces of the bastions, the former being set too far inwards in relation to the latter; compare WRE/5/2/6. The radial buttresses are shown extending the full 26-ft depth of the crossing arches on the cardinal axes. They were built about 1 ft 6 inches shorter; see WRE/5/3/9. No ink dots mark the inner wall of the lower drum, possibly because these would have confused the reading of the plan at peristyle level, where the radial walls are shown as two interlocked masonry blocks: the inner blocks are the jambs between the windows with pilasters on their front faces and the outer blocks the pilaster responds on wall of the drum. Compared with WRE/5/2/4, the outer wall of the drum has been widened from 4 ft (the built dimension) to 4 ft 6 inches and the peristyle columns have been narrowed from 3 ft 3 inches to 3 ft. They are now centred on the outer wall. They were increased to 3 ft 6 inches diameter in the fabric; see WRE/5/3/9. Sketched in pencil in the lower-left segment, probably by Wren, are niches on the internal and external faces of the pier mass and square piers on the insides of the peristyle columns. Both changes prefigure the final design; see WRE/5/3/8. The scale of the drawing is the lower scale bar at bottom left, is inscribed ‘5’ and ‘10’. Above this is an unrelated, smaller scale (10 ft to 0.7 inches). Written above this in a later 18th-century hand (probably Robert Mylne's) is a note referring to the lower scale, ‘Scale of 10 ft in an inch’. For other inscriptions in this hand, see WRE/4/1/4.

Access to the Wren office drawings held at London Metropolitan Archives is available only with advance notice and at the discretion of the Heritage Services Director, London Metropolitan Archives, 40 Northampton Road, London, EC1R 0HB.

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WRE/5/3/9, WRE/5/3/8, WRE/4/1/4