Church of Santa Maria e San Donato, Murano - Venice

The church is one of the oldest in the Venetian lagoon. It was originally built in the 7th century and is known to have been rebuilt in the 9th century and in 1040 AD, although it is possible that there have been more rebuildings in later times. Development of the interiors of the church and valuable relics are related to the legendary quarreling between the parishes of this church and neighboring church of St. Stefano which lasted up to 1125, when Doge Domenico Michele established the dominance of Santa Maria church by storing the relics of St. Donatus of Arezzo in it. The church and its bell tower are built of dark red-brown brick, without plastering. The bell tower stands separately. The main entrance to the church faces west, but the most impressive facade is the colonnaded east side, which faces a canal. The colourful stone mosaic floor of the church, including the yoked "cocks on the floor of San Donato, in Murano, who are carrying a fox" dates from around 1140, and bears superficial repairs. The relics of San Donato are located in a marble sarcophagus. Behind the altar there are four rib bones, hanging from wires. The bones are more than 1 metre long. According to legend, these are bones of the dragon slain by St. Donatus in Greece. It is possible that these bones are from large extinct Pleistocene mammals.

https://www.wondermondo.com/cathedral-of-santa-maria-and-san-donato/