Castello was one of the earliest parts of Venice to be settled (fifth to sixth centuries). The district takes its name from the castle that stood there and which provided defence from attacks from the sea. Here is the ancient Arsenal, that was an essential part of the life of the repubblica. Cathedral of San Pietro di Castello For many centuries the cathedral was under the authority of the Patriarch of Grado. In 1451 Venice obtained its own patriarch. hence the church became cathedral. As a result of the dignities that were suppressed by Napoleon in 1807, San Marco (Saint Mark's) became the new cathedral and instead of just being a chapel of the Doge's it became the seat of the Patriarch Antico Arsenale (Old Arsenal) It can be recognised by its terracotta walls and squares towers. From the thirteenth century it was an essential part of the life of the republic.

The Arsenale of Venice is an ancient complex of shipyards and workshops that constitutes a very large part of the island city of Venice, at its eastern end. It was the heart of the Venetian naval industry from the twelfth century and is linked to the most flourishing period of the life of the Serenissima: thanks to the imposing ships built here, the Venetian Republic managed to contrast the Ottomans in the Aegean Sea and conquer the routes of northern Europe . Thanks to its organization, the Venice arsenal has anticipated the modern concept of a few centuries, intended as a production complex in which specialized workers carry out the individual assembly operations of a product successively, along an assembly line and using standard components . It represents the most important example of a large production complex with a centralized structure of the pre-industrial economy. [1] The surface extends over an area of ​​48 hectares [2] (15% of the surface of the city [3]), while the number of workers (the arsenalotti) reached, in periods of full production activity, the average daily quota of 1500-2000 units (with a peak of 4500-5000 registered in the Book of workers), that is, from 2% up to 5% of the entire city population of the time (about 100,000 inhabitants). The complex is the only example of a shipyard and weapons factory that has always maintained the same nature and function, for seven centuries, even after the decline of the Republic of Venice