Achterom
The Achterom started as a canal to form a connection between the Breed and the Zuiderzee. The original name was Burchwal, or Wester Burchwal. This canal was deepened and widened in 1580, to be narrowed again 30 years later by widening the quays. In 1654, the moat was not filled in, but overcolded creating a road and a sewer. This new street was called Achterom, because the street was behind what was then the main street of the city Hoorn: the Great North. A large number of buildings on the Achterom belong to buildings on the Grote Noord, these are buildings that served as a garden house or storage room.
https://nl.wikipedia.org/wiki/Achterom_(Hoorn)