For centuries, Micklegate Bar has enabled York's rulers to control (and tax) people travelling overland into the city from the southwest.
The oldest part of the structure is the outer gateway arch and parts of its passageway. These were constructed during the early or mid 12th century from recycled Roman gritstone blocks. The gateway controlled access through an earth bank that surrounded the city. (Patches of slightly rougher stonework on the bar's side walls indicates the approximate size and shape of this earth bank.)
Although Micklegate Bar contains re-used Roman masonry, it does not lie on the route of the Roman road into the city from the southwest. Excavations have shown that the Roman road - and the associated gateway into the walled colonia or civilian settlement - lay approximately forty metres further west - i.e. slightly closer to the current railway station.
Twelfth century records refer to Micklegate Bar as 'Micklelith' ('Mickle' = great or large amount, 'lith' = stone).
Records from 1196 suggest that a second storey (in the form of a house) may have been added to Micklegate Bar towards the end of the 12th century. The structure was definitely altered in the second half of the 14th century, when the height of the structure was increased (to accommodate a portcullis) and a barbican was added to the outward-facing (southwest) elevation. Both extensions were constructed using magnesian limestone and the barbican included two sally-ports, one in each of the side walls.
The barbican suffered a partial collapse in 1810 and it was demolished in 1826.