We were told that the mill where we have taken our olive harvest for years was hosting a supper in aid of the restoration of the local church. ‘Why don’t you come?’ I was asked to pay at the local bar, but they only wanted my name and how many in our group. We were to meet at five on Saturday afternoon in the forecourt of our nearest olive mill. We joined a large group of locals gathering around an authoritative-looking woman with a microphone and a loudspeaker system that spluttered and refused to work. She started to give the group around her the background to the draining of the land we were about to explore in the Val di Chiana.

It has never had a river, just swamps fed by the streams from the surrounding hills. The Etruscans had drained the valley and cultivated it, and so did the Romans. After the end of the Roman Empire, the population dwindled and left the lowland for the hills. Malaria became endemic.

From the middle of the 18th century, Tuscany was ruled by the Grand Duke Pietro Leopoldo II from the Lorraine branch of the Habsburg family. The Etruscans had cultivated this valley from at least 600 BC, and the Romans followed them. It was only when the population decreased and retired to form hilltop towns from the 5th century AD onwards that the lowland was no longer cultivated and swamps and malaria returned. That was the valley that Leonardo da Vinci explored. His map is now on display in the current exhibition in the Queen’s Gallery.

About seventy of those gathered at the olive mill started out on a guided walk over precisely the flooded area on Leonardo’s map. The rough tracks follow the original ones for ox carts, still hard and bumpy but just slightly raised above the cultivated land. A few willow trees edge the fields, planted to supply pliable twigs to bind the grapevines. Every bush or tree here has its use in a working landscape. Distinctive rectangular farms with a square pigeon cote at the centre were built in brick to house the families that cultivated the land. Without motorised transport, young people walked or went on carts to neighbouring farmhouses and there was much intermarrying. The ‘village idiot’ was accepted and cared for by the community. He or she could still be found in recent times.

Our walk was three kilometres long with frequent stops at the shrines to the Madonna usually found at the crossroads. Our guide, who has just published a book on the area, told us more when we paused at the crossroads, but the clumsy loudspeaker apparatus usually caught up with him far too late.

Footsore, we sat down in one of the churches the proceeds from the supper was to restore. It is a round church jutting out into the road to Arezzo. Although destroyed by the Germans during their retreat in WWII, it has been restored on the same foundations and is consequently still a rather dangerous point on the road to Arezzo. Half a mile further on we finally arrived at the olive mill, now filled with long rows of tables both inside and out. More than four hundred diners were expected. Many more came.

We found a place with some people we knew. Next to me was a group from Borgo San Sepolcro in the Tiber valley, the birthplace of Piero della Francesca and one of my favourite towns. They were part of an organisation formed to restore small country churches that were neglected by the headquarters in Rome. Food was being distributed by young children: pasta in tomato sauce, meat, gravy, oven potatoes and beans in a similar sauce followed by slices of cake. We offered 20 euros each and were only asked for 15. I feared there might not be much of a profit to restore all those roofs.

I have always enjoyed visiting this olive press because the owner has such a kind and gentle manner and the atmosphere is always very special when we go there for the olive harvest each year. This year there are so few olives that I fear he will not have much business.