To supplement the soldiers' accommodation in the casemates of the Redoubt, construction was begun in October 1804 on a separate barracks (later known as Grand Shaft Barracks), designed by Twiss to accommodate 700 men, on land between the Redoubt and the cliff to the south. Towards the cliff, the ground was levelled to create a parade ground; behind it, stepped terraces were created in the slope up the hill on which were built three parallel ranges of three- and four-storey barracks blocks: first (facing the parade ground) were a pair of blocks, one for soldiers, one for officers; then, on the next terrace up, was a longer block for soldiers plus a small block for Staff Sergeants; then, above that, was the Field Officers' quarters. (Further terraces beyond later accommodated a gymnasium and stables). Access to the terraces was provided by a long flight of steps rising from the far left corner of the parade ground (as viewed from the cliff top). The right-hand side of the parade ground was enclosed by the Officers' Mess, whilst a Canteen (later termed 'Regimental Institute') was built facing it, on the left-hand side; the remaining side of the parade ground was left open (providing a clear view across the harbour from the cliff top). Ancillary buildings were sited on further terraces above and beyond the Canteen (ranged along the left-hand side of the flight of steps); further buildings were added in the 1860s, including additional married quarters. Barrack accommodation on Western Heights was further increased by the building of another barracks to the south-west, South Front Barracks, in the 1860s. In contrast to the Grand Shaft Barracks, which had come to be seen as vulnerable due to technological advances in artillery, the accommodation at South Front Barracks was mainly built within bomb-proof casemates within the ditch of the southern defensive line (which was constructed at the same time above Archcliffe Fort). Between these casemated barracks and the Citadel Road, married quarters and ancillary buildings were provided, on a series of three stepped terraces built into the hillside. The casemated barracks had accommodation for 400 soldiers and the married quarters accommodated a further 120 married soldiers with their families. While the married quarters continued to be occupied in the 20th century, by 1912 the casemates were no longer in use as barracks, serving instead as offices for the Royal Garrison Artillery. To the west