A small territory with a wealth of history, in the Middle Ages Borgo di Terzo played an important role in the economy of Val Cavallina.
Borgo di Terzo is one of the municipalities with the smallest area in the valley (just 1.86 square kilometres for slightly more than 1,100 inhabitants). However, in the late Middle Ages, as a result of an economy based on ironworking and cereal milling, Terzo and its village performed a wealth of activities and trade, to the point of becoming the political and economic centre of the middle and lower valley.
The rule of the Terzi family was decisive for the development of Terzo and its village. The foundation of the Terzo Castle (which no longer exists) is due to this family.
Important buildings remain, however, to testify to the history of the village set in the central part of the Val Cavallina valley. These include the Monastery and Church of San Pietro in Aria, the Monastery and Church of San Michele, Palazzo Terzi, the village (with its mills, forges and ironworking hammers), but also the Torrazzo (tower), the courtyards of the notary houses and the Church of Santa Maria Assunta with the Oratorio dei Disciplini (which have recently been restored).
