Chiusdino, Monticiano, Sovicille. Names that may mean little to many: they are small villages dotted along the Val di Merse, a lovely corner of the province of Siena, in the southern part of Tuscany. Gentle hills, dense forests, and a few watercourses that flow, sinuous and silent, between one bend and another of the landscape.
Here, among the beauties of Siena, the Metalliferous Hills and the first outskirts of the Maremma, the Merse River, a small tributary of the Ombrone, provides the backdrop for a beautiful and little-frequented excursion: a green walk that first leads to an ancient forgotten castle, with a name that is already a story in itself, and then, on the way back, to a freshwater beach that in summer becomes a wonderful oasis of refreshing respite not to be missed.
The small village of Brenna and the Merse River
The starting point of this excursion, perfect for the summer period, is Brenna, a hamlet of the municipality of Sovicille that comprises a few houses gathered around the church, a few kilometers south of Siena. Beautiful for its winding alleys and the stone walls of the houses, the village has a history older than its tranquil appearance might suggest: the first document mentioning it dates back to 969, a text by Emperor Otto I who, visiting this area, already called it a village perched on the banks of the Merse.
And it is the river that is the real protagonist of the surroundings. Its waters flow along the village, clear and a deep green. For centuries the Merse (though locals refer to it in the feminine, “the Merse,” and we follow suit) has been a fundamental resource for the local community: along its course rose numerous mills, powered by a system of canals and sluices built already in the medieval era, partly by the monks of the nearby Abbey of Torri. Some of these buildings and their hydraulic mechanisms are still visible today, camouflaged among the roots of trees, a silent testimony to an agricultural economy that revolved entirely around water.
The Merse runs for seventy kilometers, starting from the Poggio di Montieri, one of the highest peaks of the Metalliferous Hills, a range of Tuscany independent from the Apennines. Before turning toward the Ombrone, the river flows northeast. And it is here that the trail enters the heart of the High Merse Nature Reserve.
The trail to Castiglion che dio sol sa
From the small settlement of Brenna begins CAI path number 400, which winds along the Merse on the left bank. The route threads through an orderly forest of Turkish oaks, downy oaks and holm oaks that rise along the riverbank. Walking among gorges and stone footbridges, one encounters the steccaia, an ancient hydraulic engineering work built by the monks to regulate the flow of water, from which a millrace still functioning branches off today.
However, the objective of the walk is to reach another destination: Castiglion Balzetti, universally known as Castiglion che dio sol sa. The name, as unusual as it is apt, arises precisely from the castle’s remote, isolated position, so hidden in the forest that it seems unreachable to anyone who does not know the path.
To reach Castiglion che dio sol sa you must travel just under five kilometers of trail from Brenna. The path along the Merse is almost entirely shaded by the forest, and the river’s flow provides relief, making it an ideal excursion for the summer months. The scenery of the river environment is beautiful. After about three kilometers the path leaves the riverbanks and enters a denser forest, following the course of a small, tributary ravine. Here, the temperature drops even more, noticeably.
You will encounter the ruins of a splendid mill, the Mill of Ricausa, named after the small stream that runs through this wilder forest area, decidedly fascinating. The ancient building, of medieval origin but in use until the early 20th century, was built on a rock spur: even today one can clearly see the well-preserved structures, the millstones’ wheels and the wooden driving beams.
From the Mill, one last effort remains: with a sharp ascent the path leads to the entrance of Castiglion che dio sol sa. The earliest historical mentions of the castle date to 1262, after which it experienced a period of abandonment starting in the 14th century, continuing into the decline of the Republic of Siena. Today there are imposing ruins recently subjected to substantial restoration, which suggest the beginnings of a possible reopening.
The freshwater beach on the Merse River
Having completed a nice circuit around the castle and enjoyed a short break in the clearing in front of it, the route does not continue along CAI 400, which makes a wide loop to reach the small village of Montarrenti, but instead returns along the outbound path until it reaches the point where the trail left the Merse to enter the small Ricausa valley.
Here, following a forest track or walking through the shallow water of the small stream, you arrive at a ford across the river. The crossing here is easy, there is no current and the water is not deep, but once on the other bank you encounter a beautiful little beach, with a rocky area and a sandy stretch, under the shade of tall trees. Opposite, a deep emerald natural pool formed around a white rock in the middle of the Merse’s bed; it’s an irresistible draw: you must drop every burden ashore and enjoy a wonderful dive into the cool currents.
It is the most beautiful and least frequented freshwater beach along the Merse river, which in summer becomes a colossal public pool for everyone’s enjoyment. It will not be hard to find other people swimming, diving, and relaxing in other spots along the river as you walk the banks.
Finally, you can finish the circuit by re-crossing the river and heading back to Brenna via the outbound path. Alternatively, a track leaves the beach and ends up joining the Calcinari road, a white path that in about half an hour of walking brings you back to Brenna from the opposite bank of the Merse.
