The ancient monastery of St. Donato is in the Municipality of Piegaro and takes its name from the Jerna creek that flows nearby.
Few traces remain of the monastic complex. Today the rooms annexed to the church are colonial residences. Instead the parish church, with the title of St. Donato, was extensively renovated in the 19th century and is in a fair condition. The façade has an ashlar facing. The exterior of the Church is completed by a square bell tower.