There seems to have been a church at Islip in Saxon Times, but the oldest part of the present church only dates to the end of the 12th century. This is the line of arches and columns between the nave and the north aisle. The church was largely rebuilt in the 14th century, and a tower was added in the 15th. In 1824 a fresco dating from about 1360 was discovered in the south aisle; it is now covered over, but a framed reproduction is on display in the church. The font dates from the 15th century. An older font, reputed to be that in which Edward the Confessor was baptised but actually dating from the 14th century, used to stand in the ‘King’s Chapel’, a building to the north of the church which was demolished as unsafe in 1780. The font is now in All Saints, Middleton Stoney.
The church was badly damaged in the Civil War, when Cromwell’s troops won the battle of Islip bridge (1645). The chancel was burnt down. It was rebuilt in 1680 by the village’s great benefactor, Dr Robert South, rector from 1678-1716. He also re-roofed the north aisle and added an oak communion table, which is now located in the lady chapel. In 1446 it was confirmed that Edward’s gift of Islip to Westminster had been made on the condition that a chaplain say masses daily in St Edward’s chapel for the souls of the king and of his ancestors and successors. It is likely that this had been the case intermittently since 1203. The chapel as described by the Oxford diarist Thomas Hearne in 1718 was situated to the north of the church and was a small building, 21 ft by 45 ft. At the time of the millenium celebration in 2005, the Channel 4 television programme Time Team attempted, without success, to locate the chapel. Possibly already from 1203 the abbot of Westminster would have had a house in Islip. This first house seems to have been close to the church, but in the 14th century Abbot William de Curtlington built himself a much finer and more splendid residence on the eastern corner of the village. The church was substantially rebuilt in 1861, when church reform was prominent in English political and ecclesiastical circles. The reforms originated with the Oxford movement’s insistence on more historical liturgy and extended into architecture with the Ecclesiological Society (founded in 1839 as the Cambridge Camden Society). Most of the stained glass in the windows dates from the 1861 restoration, the older glass having probably been destroyed by Cromwell’s troops. But the window depicting the risen Christ and St Peter in the south wall of the chancel dates from 1904, and that in the east end of the south aisle, depicting St Nicholas and St Christopher, from 1948. Details of the lost paintings can be found in J.C.B. Lowe’s article published in Oxfordshire Architectural and Historical Society’s Oxoniensia. LXV. 447.
In 2005 the church undertook a campaign to refurbish the fabric and add modern amenities including a lavatory, a kitchen and improved heating and lighting. The final phase of the project was the installation of a glass screen in an archway at the west end of the nave. The screen, designed by the renowned artist Nicholas Mynheer, depicts Saints Nicholas (for whom the church is named) and Edward the Confessor, along with symbolic portrayals in their lives and of the three persons of the trinity. It also shows the village of Islip in the background.