The church's origins are murky; the idea of a now vanished Saxon foundation is a claim that many church guides like to toy with, but Bagendon has more evidence than most. The main basis of this claim stems from many of the multiple windows in the tower, which are monolithic with tiny openings and appear to come from a Saxon building, having been reset here. Whether these openings are Saxon or not, the earliest surviving fabric of the present church building dates from around 1100, comprising the north nave arcade and the lower two stages of the tower. There are also traces of the base of the Norman chancel arch at either end of the present step into the chancel. The tower was formerly split and storeyed into two chambers where priests from Llanthony Secunda Priory in Gloucester (whose chaplains served the church during the 12th century) would lodge.

Hereafter, few changes were made to the church's fabric for some 350 years, with the only exception being the insertion of a two-light window in the southwest nave wall in the 14th century. The next major work to be carried out in the church did not occur until the 15th century, sponsored by the Weavers' Guild of Cirencester, who now held the church and whose chaplains from their home chantry of the Holy Trinity in Cirencester's parish church were responsible for conducting services. This work involved the chancel and chancel arch being rebuilt sometime in the 1460s along with almost every wall and window in the nave and north aisle. Thus the Norman nave arcade now stands marooned in a sea of simple but distinctive Perpendicular Gothic. The south porch and the saddleback upper stage of the tower were also added during this time, and the tower diagonally buttressed. The eastern end of the north aisle was probably a chapel dedicated to the founder at this time, an idea suggested by the height of the aisle's east window making allowance for an altar underneath, and the damage to the eastern portion of the nave arcade suggesting that some sort of parclose was once present to separate this chapel from the remainder of the building. Additonally, the tombstone of the founder in question was discovered under the north wall (now located in the tower and unfortunately inaccessible when I visited).

After the 15th century, the church then faced another equally long period of little rebuilding (which is not particularly unusual in this post-Reformation period), again with the only exception being a window, this time a late 16th/early 17th century one in the west wall of the north aisle. During the 18th century, the southern pier of the chancel arch was partially hacked away in order to install a triple-decker pulpit, and later in the same century (or possible early in the next) the nave and chancel's present wagon roofs were installed.

However, yet to come is the dreaded Victorian restoration. In 1832 (yes I know that this is not during the Victorian era but I am content to lump all of the 19th century changes together!) it was deemed necessary to raise the nave floor due to the effects of flooding, as the level of the church floor lies below the level of nearby Perrott's Brook. In doing so, the tower arch had to be raised as well, and the original Norman work was lost and replaced with a rather severely cut imitation. More alterations came at the end of the century, with two dormer windows being added to the nave in 1877 (an addition which the church guide scathingly describes as 'unsightly') and the nave, aisle, and porch were all given new roofs. The main restoration was carried out by Sidney Gambier-Parry (half brother of the composer Hubert Parry) in 1888-89. This involved removing the raised floor (which apparently had been ineffective against the flooding anyway!) and laying down modern flooring, rebuilding the north wall of the aisle and inserting additional windows, tacking a vestry onto the north of the building, and replacing almost all the fittings and furniture in the church, including the pews and pulpit (this time not triple-decker!).

The church also saw a few changes in the 20th century; the north side of the chancel was re-roofed in 1933, with the south side following in 1962, along with the comprehensive re-roofings of the nave, aisle, porch, and vestry. At the same time, the 'unsightly' dormer windows were removed (and it is revealed in an offhand remark by the church guide that they were taken to Canberra for some reason!) and the south porch entirely rebuilt and reinforced (reusing the original materials) due to significant subsidence.

The information here has been taken variously from the church guide (leaflet available from the church) and the Historic England listing.

Bagendon is a textbook example of a quintessential Cotswold village (and I use the word 'village' generously for a settlement this miniature), a slice of idealised English country life. Whilst I'm sure the house prices would be eyewatering and the local ballot papers be staunchly blue, it cannot be denied that Bagendon is one of the most picture-perfect areas of the country imaginable. The church is what makes this view, the centrepiece of a rich ensemble, but the view simultaneously augments the church, which is cradled in a shallow dip in the centre of the village among lush trees and golden Cotswold stone cottages. With all this in mind, the church's situation and aspect are undoubtedly up there with the most pleasantly and adorably beautiful I have seen with my own eyes.

Entering the church does nothing to change this cutesy feeling. Whilst the space does not feel particularly ancient, with the Victorians having neatly obliterated that feeling, the closeness and shallowness of the architectural elements make the space feel homely and quaint, with the squat chancel arch and nave arcade doing much to bring the dimensions of the space inwards around the visitor. Whilst not the darkest of interiors, the electric lighting is still very much needed in order to comfortably visually explore the place, although this lighting is distinctly unnatural and deadens the space a little. Despite the fact that the church is so small and the fittings mostly so unimaginatively Victorian or later, it should absolutely be explored thoroughly and with an open mind. And try the tower door as well, it might be open this time!

As with other media of medieval art in English churches, it is a precious rarity for medieval stained/painted glass to have survived the religious and political upheavals of the intermediate centuries to reach us in the present day in any sort of complete form. Many medieval churches cannot present anything but the most meagre of scraps to attest to their once flourishing schemes of window decoration, and whilst Bagendon may appear to be in that category in terms of the integrity of what is to be seen at the church, the glass here is towards the higher end of the national average regarding volume and interpretability of its fragments. There are four windows containing 15th century glass fragments in the church: the northeast and east windows of the aisle, and the two south windows of the chancel.

The southeast chancel window is the most interesting in my opinion. The fragments here were reassembled in memory of the eleven Bagendon men who lost their lives during World War 1, with a stylistically complementary inscription to them in the lower left corner. The window is pleasingly colour-coded with rich, golden-yellow hues in harmony with a range of blues. The left hand pane contains fragments of a scene depicting the crucifixion, with Christ's nailed feet and right hand being visible, as well as, most prominently, the skull of Adam buried beneath. The right hand pane has a heraldic shield of one of the wealthy members of the Cirencester Weavers' Guild at its centre, presumably the insignia of one of the bankrollers of the 15th century remodelling of the church, and fragments of a depiction of St. Catherine of Alexandria below.