Chancels and chapels would have been divided from the nave and side aisles by a large screen under the chancel arch with a large rood or crucifix attached to it. It would have been possible to walk across the top of the screen on the rood loft whenever it was necessary to lower the crucifix for processions, or alternatively as access to read the gospel from here on ceremonial occasions. The two existing spiral staircases in the walls of the aisles would also have given access to this loft.
The main body of the church was left as an open space with no pews and shut off from the altar. It could then be used for all variety of public occasions. In medieval times the walls would have been plastered and painted with biblical pictures and portraits of saints.
After the Reformation the church was striped of its statues. Worship became more sober and the "rood" was taken down in 1548. In 1538 Thomas Cromwell ordered that an English Bible should be set up in every parish church. The new emphasis was on the Bible being read in the native tongue instead of Latin. Towcester's Treacle Bible still retains the chain by which it was secured to a reading desk and available for the congregation to read.