Most of St. Andrew's Church as you see it today is the result of a reconstruction carried out between 1883 and 1888 under the direction of George Sutherland, the clerk of works at Castle Ashby. The south aisle and the porch were rebuilt in 1883, the roof and the chancel in 1884-5 and the north aisle in 1887-8. There are nevertheless a number of interesting features which survive and the restoration appears to have preserved the original footprint of the building.
The oldest surviving part of the church is the tower which dates from about 1200. Whether this was a "new" building or a replacement of something earlier is not known but no church is recorded in the Doomsday Book (1086). Nor do we know what the rest of the church looked like as the nave, aisles and chancel date from about 1340 and obliterated almost all the earlier work. This rebuilding was probably commissioned by Laurence de Hastings who was created Earl of Pembroke in 1339. The Hastings-family had acquired the manor of Yardley by marriage in the mid C 13th and were created barons in 1290. It was perhaps to celebrate the family's promotion that Laurence decided to rebuild both the church in Yardley and also the manor house, the remains of which stand immediately to the north of the church. And he built on a grand scale, creating a church which was far larger than would have been needed for the village; it was built to impress both subordinates and visitors. At least their family name survives in that of the village.
Some fragments survive from this rebuilding, perhaps the most obvious being the south door through which you entered. Below the window in the south aisle are two statue brackets, the one on the right representing a "Green Man". A corbel now almost hidden by the organ has been said to be a bust of a man suffering from tooth-ache "but [his gesture] probably means some obscene challenge". (Pevsner). The triple seat on the south side of the chancel and the piscina in the south aisle are mostly restorations but are quite prettily done. The nave piers are also original and it is worth noting that the capitals on the north side appear to be of a slightly later date than those on the south side. The bays are double chamfered (i.e. with two layers of mouldings), an expensive feature in a parish church.
In terms of more modern features, the Morris window in the chancel is worth noting. The chancel also contains on the north side a memorial tablet to Rev. Edward Lye by William Cox whose family produced the best memorials in eighteenth century Northamptonshire. Lye has a page or two in the Dictionary of National Biography as the compiler of an Anglo-Saxon dictionary which was much used by his friend, Dr Johnson in the compilation of his Dictionary. The tablet on the south side of the west window commemorates Humphrey Betty, chaplain in the Turin Embassy before becoming Rector of Yardley Hastings in 1695. It was presumably in the nineteenth century restoration that the owl(?) flew from the left hand side of his tablet to sit on top of William Underwood's monument. The chandelier in the nave was manufactured by Cocks & Son, Birmingham and presented to the church by Rev. G Rooke in 1808.
Finally the bells should be mentioned. A new set of six bells was cast by Henry Penn in 1723, paid for no doubt by George, 4th Earl of Northampton whose arms are incorporated on the body of each bell. "They are the finest work by Penn I have seen" writes Michael Lee, author of Henry Penn, Bellfounder. The gift of these bells was not however an unmixed blessing for the church as some fifty years after they were installed, the SW corner of the tower began to subside. The tower walls were reinforced and a new buttress built. These measures stopped the subsidence but the tower still leans to the west.