Probably in the C15 the chancel arch was rebuilt, the chancel squared off, and the W belfry added.
The S porch was added in the early C16.
There is a C16, 2-light uncusped window in the chancel N wall
a cusped, C15, 2-light window in the S wall.
A building break in the S wall may indicate the springing of the former apse, and a C12 window head has been reset nearby.
The N wall has a single, small, C12 window set above a C12 doorway with a round head and plain jambs.
The N door is of three battens and may be C12
it has two strips of decorative C12 ironwork.
There is also a 2-light, mid C14 window with tracery in the N nave wall towards the E end.
The S nave wall has a C12 window just to the E of the porch
The S door is mid C12 and has three orders.
The outer two have chevron and stand on shafts with chip-carved abaci and cushion capitals.
The brick S porch was added in the C16 and has a depressed-headed opening under a hood mould and three uncusped brick lights on each side.
INTERIOR The C15 chancel arch has two chamfered orders dying into the side walls.
It has four, probably C15 posts with curved braces supporting a moulded cornice.
The chancel roof has C15 moulded wall plates and an exposed pair of arch braces in the centre, but is otherwise plastered.
Stained glass: some C14
HISTORY Mashbury the place is mentioned in the Domesday book of 1086
the church was not included and the existing building of the C12 probably represents the initial foundation of a church there.
SOURCES Buildings of England: Essex , 593 RCHME Essex II , 186 Council for the Care of Churches Report, 1983 REASONS FOR DESIGNATION The church of unknown dedication in Mashbury should be designated at Grade II* for the following principal reasons: * Very complete small church of the C12, including some original windows
windows. * C16 brick porch