Alberobello, i trulli Italy  heritage UNESCO

Alberobello is not an ancient town, although its origin is cloaked in folk myth. It appears it has its origins in the 15th century, and by the 16th had a mill and tavern built by one of the Counts of Conversano, Gian Girolamo II, in the hope of attracting farmers to create another patch of feudal Italy that was in his control rather than the distant Naples lords..

Folklore history says that the trulli were created at this time, so that the Napolitan taxes on permanent settlements and buildings could be avoided. Building without mortar enabled the houses to be dismantled as soon as the locals got wind of a tax inspector coming their way - and rebuilt once the tax collectors had completed their inspections.

This is an improbable distortion, but persists in popular mythology. It is likely that the origin of trulli is much older. The Murge, or Mugia, high plains of the central Puglia, were not ideal for agriculture, being of thin red soil on top of limestone. Until a few hundred years ago the area was mostly covered with oak forest - indeed Alberobello draws its name from the "Sylva Arboris Belli", the extensive woodland which covered the area before being worked for farming purposes.

Even today it is difficult to plough or rotavate a field without having to spend much time dealing with the quantity of stone upturned. Historically this provided most of the material for constructing the extensive dry-stone walling which characterises the region. And the trulli.

The practical advantage of a trullo (trulli is the plural) construction is that thick limestone walls give protection from the cold of winter. Conversely, in summer the temperature inside a trullo is a welcome several degrees less than the outside. So you have a combination of a widely available building material with a practical advantage.

But why did trulli evolve as they did, with a construction unique in the world?

Neither the myth nor the commonsense approach answers this question fully.