Ian Collins looks at East Anglia's very special round-towered churches

Sometimes it seems that the immense canopy of sky above the level East Anglian landscape is held aloft on flint columns – the round towers of our region's most distinctive medieval churches.

Nowhere is this effect more marked than at Haddiscoe, whose church of St Mary soars above a marshy view from Beccles to Acle, and to similar flinty fingers pointing out Herringfleet, Hales, Raveningham and Lound.

In his classic 1958 guide to The Round Towers of English Parish Churches, Claude Messent wrote of this beacon building: 'Here we have what might be called the champion of the round towers. Situated on a high mound above the marshes its site commands a fine view towards the east coast.

'It is a lofty structure of definite Saxon date. Four storeys in height with battlemented parapet at the top, which has a very pleasing checkered pattern made with knapped flints.

'Each storey is unusually divided by bands of stone. The triangular headed windows to the belfry storey are unusually ornamented examples of Saxon work.'

Of 185 round-towered churches in England, 177 are spread across Norfolk (126), Suffolk (42), Essex (seven) and Cambridgeshire (two). Most were built during the 150 years from AD 1000, thus spanning the Saxon and Norman eras and, evidence suggests, areas of Viking settlement.

Ruins or documentary evidence show that many more have been lost to us – at least 30 in Norfolk alone.

The origins of such a vivid vernacular style are still shrouded in myth, with the most startling claim being that they began as well shafts exposed when a great flood washed away a vast layer of land.

Eerily, photographs from the beaches of late Victorian Dunwich and 1950s Pakefield illustrate this very phenomenon.

In AD 937 King Athelstan decreed that local leaders desiring the status of thegn must raise bell towers on their lands – possibly resulting round towers might then have become turrets of refuge in ensuing times of trouble.

It was also long assumed that East Anglia's lack of local stone forced a cylindrical (or, in flawed practice, a tapering oval) shape, because knobbly flints are unsuited to the construction of corners.

But Norfolk building conservation expert Caroline Davison notes: 'Many of the church naves, which often pre-date the round towers, use flints as perfectly adequate quoins for square corners.

'In addition many of the round towers are partially built from an indigenous stone called ferrugenous conglomerate which also works well in square corners – but the builders chose not to use it that way.'

Cultural factors now seem crucial. In the decades on either side of the Norman Conquest East Anglia, and Norfolk especially, had stronger links with coastal communities around the Baltic and North Sea than with the rest of England.

Round towers can be traced across northern Germany, Scandinavia and the Orkneys.

Each ancient church – however grand or humble – is a historical jigsaw puzzle, with interlocking pieces from different periods.

Round tower models are no exception.

The earliest towers are of flint rubble with wide joints of hard mortar whose formula was forgotten in the Middle Ages.

Some contain reused Roman bricks. Many in West Norfolk include carrstone quarried at Snettisham, or red and white Hunstanton chalk.

Restorations from the late 14th century to the 1530s rebuilt plain top storeys as octagons, with quoins of the eight corners cast in red or yellow Tudor bricks.

Flints also vary widely, from the rounded shapes of those found on beaches and in gravel pits to the most fantastic and blackest forms dug from chalk pits.

Some towers were refaced with glittering knapped flints, possibly dressed square and laid in a chequer pattern with alternating brick headers.

Each round tower is thus unique – from the Norman arcading of Little Saxham near Bury St Edmunds, to the detached towers at Little Snoring near Fakenham and Bramfield near Halesworth (the former separated from the body of the church over time, the latter from the outset).

Perhaps the oddest in our odd assembly is at Higham, near Hadleigh. It was built as late as 1861 to a plan by Sir Gilbert Scott – designer of London's Albert Memorial.

The Round Tower Churches Society has its own website (www.roundtowers.org.uk).