Its 11th-century origins are now mostly hidden behind the results of extensive restoration work undertaken since the 18th century; but some Saxon-era fragments remain, and reused Roman building materials can still be seen in the walls.

The west wall of the nave was built almost entirely of rubble and stones salvaged from Roman-era sites nearby, and had brick quoins.

[1] The first structural change came in the 12th century, when the east end of the nave was given arcades, each with two bays, on the north and south sides.

These aisles are not homogeneous in style – almost every column and arch is a different width or height – suggesting that they were built over a long period of time, possibly even extending into the 13th century.

[1] The fortunes of the church declined in the 17th and 18th centuries, and repair work had to be carried out several times, including to the roof and the south aisle (which was completely rebuilt).

In the 19th century, the porch, chancel, belfry and the relatively new gallery were all altered, and the Saxon-era west entrance door was blocked.

[1][2] The churchyard is large and has a wide variety of gravestones and rarer wooden graveboards from the 18th century onwards.

[3] The carvings on gravestones of that era are often gruesome, in Sussex and elsewhere,[5] and at Walberton there are three examples detailing their victims' causes of death.

The white slab shows Cook crushed under a fallen tree, watched by a laughing skeleton to the left, a hat-wearing man (who is holding an axe) and Father Time (carrying his traditional scythe and hourglass) to the right, and a company of trumpet-playing angels above.

It has a chancel, nave with north and south aisles, porch, tiled roof, and a shingled spire which sits on top of the weatherboarded belfry.