This large and imposing church is a relatively rare example of a building better understood by examining the inside first.  Viewed externally, the S. aisle windows are thoroughly confusing, but even the fact that the aisle extends the full length of the building is unhelpful for it is difficult on that account to make out the church plan. Inside there is no such problem:  the chancel and nave are two bays and six bays long respectively, the S. aisle (only) extends alongside the chancel, but both aisles continue for an additional bay to  westwards embrace the tower.

 

In fact the oldest work within comprises the late thirteenth century tower arches to the nave and embracing aisles, which bear one flat and two hollow chamfers above massive semi-octagonal responds and prove aisles were already present here when the church was first built.  The tall chancel arch is contemporary (albeit this is triple-flat-chamfered) as is the two-bay arcade between the chancel and S. chapel, with double-flat-chamfered arches springing from a central circular pier, a semi-octagonal respond to the west, and a corbel to the east.   Thus the original was also of its present length and breadth, notwithstanding that the nave was subsequently rebuilt.

 

Indeed, the six-bay nave arcades represent a single, later phase (see the photograph of the N. arcade, below right).  The compound piers are composed of semi-circular shafts with capitals toward the openings and continuous roll mouldings to north and south, separated by casements.  The roll mouldings towards the nave continue up above the level of the arcades to divide the two-light clerestory windows, and a continuous horizontal roll moulding runs beneath, in a design seen at many East Anglian churches, one of the earliest dated examples of which is St. Mary's, Bury St. Edmunds (Suffolk) by William Layer, where work is known to have begun c. 1424.   However, at Swavesey the form of the piers is simpler and more old-fashioned:  compare, for example, the piers at St.George's, Sudbury (also in Suffolk), admittedly with different arch mouldings above, where the work can be dated c. 1375.  Splitting the difference in the present case may or may not be reasonable, but consider also the clerestory, which must be contemporary but in which the windows on the south side are blocked in their lower halves where they would otherwise be obscured by the ridge of the S. aisle roof.  Surely this provides the clue to the understanding of the exterior, for it is unlikely that the clerestory would have been built with its S. windows partially blocked at the outset.  The conclusion must be that the S. aisle was widened and given its independent gable (having previously been of lean-to construction), after the clerestory was constructed.  Yet Pevsner (The Buildings of England: Cambridgeshire, Harmondsworth, Penguin, 1970, p. 468)  ascribed the S. aisle to the early fourteenth century, largely on the strength of some of its windows, notwithstanding that with the four S. aisle windows immediately east of the porch are not wholly consistent with any individual Gothic style at all.  Notes in the church, to accommodate some of these difficulties, suggest that the first three S. aisle windows east of the porch, were 'stretched' and the cusped transoms, added, several decades after their early fourteenth century construction (see the example below left).  But this will not really do either.  Uncusped Y- and intersecting tracery would already have been old-fashioned by either date, and if some windows were added later, does that really account for the fact that they are all the same height? 

 

This is where comparison with a third church may be germane, this time at Balsham on the other side of Cambridge, where the nave and aisles were built at the expense of John Sleford, rector from 1378 to 1401.  His windows are characterized by supertransoms unsupported by archlets, the right-angled corners of the sublights below being cusped, which is an almost identical treatment to that which the transoms receive at Swavesey, apart from the fact that, due to their larger size, here it has been necessary to employ double-cusping.  The likely truth is, therefore, that these S. aisle windows represent the original, late thirteenth century Y-traceried windows, re-set in the reconstructed aisle, perhaps c. 1400, and that when the work was done, they were lengthened to admit more light, and had their transoms added, together with the decorative cusping beneath.  Moving further east and examining the remaining windows in turn, the next is a 'new' Perpendicular window, presumably constructed at the same time the aisle was widened, made very tall and given a transom to fit the style of the preceding three, then comes a re-set Decorated window, equally all but this time without a transom, and the third is a re-set three-light window with intersecting tracery, also consistent with a late thirteenth century provenance.  The S. aisle E. window is Victorian. 

 

As for the other windows in the building, the chancel E. window (below right) is Perpendicular, with five lights, supermullioned tracery, and two tiers of reticulation units separated by latticed supertransoms.  The chancel N. windows, visible above the nineteenth century vestry, have three-lights, supermullioned drop tracery, and transoms directly underneath.  The N. aisle is lit by one four-light and five three-light Perpendicular windows in the N. wall - the first, a reduced version of the chancel E. window, and the others, the same as the chancel N. windows - and by two equal lancets in the W. wall.  The W. window to the tower is also like those in the N. wall of the chancel except that the lights are ogee-pointed.

 

It remains to make a closer external examination of the tower (illustrated at the top of the page, on the left).  The blocked Y-traceried window would obviously fit the late thirteenth century evidence inside, but what of the bell-stage?  Certainly it is Perpendicular, and Pevsner agrees, but the lights are again separated by those tall, slender mullions, and the stone is the same as that in the S. aisle – a buff brown, not entirely like that in any neighbouring church.  It is surely not unlikely that the grand re-building of the S. aisle would have been felt to demand a taller, more impressive tower, so that this would stand out above the increased bulk of the church below.  So if the use of straightened reticulation units can be extended a little from its most usual date in the second half of the fourteenth century, perhaps the decision to heighten the tower followed hard on the rebuilding of the S. aisle, c. 1410, the object being to rebalance the church's overall appearance.

 

After all these speculations, it remains to add a few words on furnishings.  At first glance, the nave and aisles appear to contain the most incredible collection of mediaeval poppyheads (there are one hundred and fifty) and there are also twelve misericords in the back rows of the chancel stalls.  However, almost all this carpentry is actually Victorian, only the poppy heads on the small benches in the N. aisle excepted.  However, the beautiful three-bay stepped stone sedilia in the chancel N. wall is original, with its cinquefoil-cusped, ogee arches supported on groups of four slender shafts. This, indeed, is work of the early fourteenth century.