In late C13 the chancel was rebuilt
in C14 the West tower added.
The North and South aisles were rebuilt in C15.
The South porch is C14.
The nave and crossing are important examples of late Saxon work.
"The church was built in about 1020 as a 'minster' or pre-parochial mission to the pagan forest and marsh dwellers. The Saxon features of the interior include the low [?], three-bay nave arcades and crossing. Clustered piers rise to bulbous capitals, like old pillows crammed under plain arches" (Simon Jenkins, "England's Thousand Best Churches"). Holy Trinity is Grade I listed - see http://www.britishlistedbuildings.co.uk/en-54346-church-of-holy-trinity-great-paxton-cambr
Late C14 embattled West tower of three stages on splayed plinth.
Beast gargoyles to centre of main cornice.
C14 West doorway (reset)
C15 West window.
C14 bell chamber openings of two lights with quatrefoil to spandrel.
C11 Nave with clerestorey of two round headed windows and part of a third similar window, now sealed.
Later parapet and beast gargoyles to moulded string course at eaves height.
C15 parapetted South aisle.
Two stage buttressing and two C15 three light windows.
C14 South porch.
C15 doorway to South aisle.
Two-centred arch of two moulded orders in square head with carved spandrels.
C19 door with C13 ironwork (reset).
Two C15 windows
one C13 doorway on South side.
C15 East window.
Interior: Late C14 tower arch.
Nave shortened in C15 when West tower built and now of two bays and sealed half-bay at West end.
The piers to the South crossing are similar to the North but the arch is C15, two centred and of three chamfered orders.
North of the chancel arch is C15 rood loft entry.
The roof of the nave is C17 and of four bays.
The chancel arch was also rebuilt in C15 and is similar to that of the South crossing
the responds are C11 and have engaged shafts divided by rolls or fillets similar to those of the arcade.
The capitals, however, were replaced by embattled dentils in C15.