This is still an ongoing discussion. For the churches in East Anglia – where the majority of these churches is located – experts from the Round Tower Churches Society can offer different explanations. For me, they look like defence towers, a  theory not accepted by those experts because of different reasons: sometimes, the tower was added to the nave long after the nave was build, or the walls are not strong enough. In other areas – like Alsace/Lorraine in France or Luxembourg – the towers are historically known as defence towers. Some were able to house the whole village in case of an attack, like Heckenransbach, where a large room is located at the top of the tower. But still, no definite answer has been found yet. Making these churches even more interesting and – in a way – “mysterious”. See the Miscallenous section for more information.