Fectio, known as Vechten in Old Dutch, was a Roman castellum in the province Germania Inferior established in the year 4 or 5 AD.

It was located at the place where the river Vecht (Fectio) branched off from the Rhine, leading to Lake Flevo, which was later to become the Zuiderzee.

Imperial Roman coinage teaches us that the castellum was built by order of Tiberius, then engaged in his campaign of 4–5 AD.

In 40 AD the emperor Caligula visited Fectio during the trip to Lugdunum Batavorum, the ancient Brittenburg.

[4] From 1 June 2023 to 31 October 2024 there is a small exhibit of the hundred most important finds in the Rijksmuseum van Oudheden.