League of God's House
Under the Carolingian dynasty Bondo belonged to the "Ministerium Bergallia", which was a dependant of the early Bishops of Chur, though after 960 it was owned directly by the Bishop. The valley church of S. Maria at Castelmur is first mentioned in 988, while the village church for Bondo, S. Martino, was consecrated in 1250. During the High Middle Ages Bondo was part of several villages that were collectively known as "di là dell'acqua" (‘across the water’), which were part of the district of Sotto Porta/Unterporta. In 1367 Bondo, together with the rest of Sotto Porta/Unterporta, joined the League of God's House (German: "Gotteshausbund"). In 1380 it was first mentioned under the name of Bondo. In German it was also known as "Bundth" while in Romansh it was known as "Buond".