Aleth was a Gallo-Roman settlement on a peninsula on one side of the Rance estuary. The bishopric was established in the 9th century. Aleth Cathedral (Cathédrale Saint-Pierre d'Aleth) was destroyed by Norman invaders in the 10th century but later rebuilt.
The site of Aleth however was not a secure one and the town of Saint-Malo had begun to grow up on a far more defensible site on a rocky islet in the estuary. In 1146 the seat of the bishopric of Aleth was moved to Saint-Malo by the bishop Jean de Châtillon. The bishopric thus became the Diocese of Saint-Malo and the abbey church Saint-Malo Cathedral, replacing the cathedral in Aleth.
Competition with the new town came to a head in 1255, when resentment in Aleth at the tax demands of Saint-Malo resulted in armed conflict. Aleth lost, and the walls, fortress and church were dismantled as punishment. The former cathedral ruins are still to be seen in the commune of Saint-Servan which occupies the area of the former Aleth.
References:The Villa d'Este is a 16th-century villa in Tivoli, near Rome, famous for its terraced hillside Italian Renaissance garden and especially for its profusion of fountains: the extraordinary system contains fifty-one fountains and nymphaeums, 398 spouts, 364 water jets, 64 waterfalls, and 220 basins, fed by 875 meters of canals, channels and cascades, and all working entirely by the force of gravity, without pumps. It is now an Italian state museum, and is listed as a UNESCO world heritage site.
Tivoli had been a popular summer residence since ancient Roman times due to its altitude, cooler temperatures and its proximity to the Villa Hadriana, the summer residence of the Emperor Hadrian I.
The Villa was commissioned by Cardinal Ippolito II d'Este (1509-1572), second son of Alfonso I d'Este, the Duke of Ferrara and grandson of Pope Alexander VI, along with Lucrezia Borgia.