Who designed the Medieval churches?

Answer 1

The majority of English stone churches were built during the late 11th century and throughout the 12th century in the Norman style (round-topped arches and slit windows without glass, using local building stone but with imported Caen limestone for the decorative parts). The plans of these churches were roughly all the same, with some exceptions, but the designs were already established in Europe long before the Normans started building churches.

Later building phases simply added to or altered the existing Norman churches, enlarging them for increased populations or inserting up-to-date windows (larger, pointed - and with glass). So there was no design involved after the original buildings were put up as part of the Norman's immense building programme.

One very clever alteration seen in many churches is the addition of two long "aisles" to provide extra space inside. This involved knocking away the original outer walls and inserting rows of arches; the aisles were then built as add-ons and the former outer walls became inner rows of arches. This sometimes left original Norman slit windows at the top of the wall, under the roof line, with new pointed windows along the new outer walls.