What is a swept yard? Just bare dirt?
I'm just going to copy-pasta the relevant part of my answer in a previous thread which covered a general overview of the history of lawns in England.
American gardening history will of course have some distinctive elements, especially in areas where the climate is markedly different, but trends are likely to have been influenced by the originating cultures of immigrants and so I feel this is relevant.
//The forerunner to lawns would have been pasture land with grazing animals keeping the grass and other plants under check for part of the year and then being used as a 'lawn' when those animals are rotated to different pastures, the scything required for the sort of regimental garden style lawns that we're now used to would have been labour intensive and the preserve of large estates. If you didn't have enough land for this to be labour intensive then it's unlikely you're using that little scrap of land for growing a garden-lawn, not when you could fit some chickens or a turnip patch on it.
The lawn of English gardens as we know it today starts to appear in the late medieval period and is associated with the emergence of lawn-games such as bowls. At first it's simply a patch of land set aside and bordered by a hedge or a fence, to be used for recreational activities rather than for agriculture.
The ornamental element comes to the fore during the Elizabethan period when there is major influence from French formal gardening, the 'signature' of which is having the 'avenue' (tree lined walkway) to your stately home's entrance be flanked on either side by a beautifully kept lawn decorated with immaculately trimmed hedges. This is primarily a status symbol, a show of control over nature and a show that one has enough spare cash and land to put together an impressive garden. There were also major influences from the Italian and Dutch schools at this time, so the English garden becomes an amalgamation of many styles, but it's the French that have the most direct impact on the prominence of lawns as being for show.
In the 18th c. the English rebelled against regimented formal gardens and introduced what is now termed 'the English garden' style. This was pioneered by Lancelot 'Capability' Brown (inspiration for 'Bloody Stupid' Johnson of Dicscworld.) The 'English style' is the closest to modern 'landscape' gardens, in which the aim is to mimic and enhance rather than to conquer and sanitise nature. The lawn was a less central focus at this stage, but it would have still been a feature.
By now a lawn was a vantage point from which to view the garden, rather than the main attraction. In the Victorian age things swung back the other way. The landscape gardens remained, but the importance of a well maintained lawn reasserted itself. The emergence of the 'cottage garden' which was designed to be suited for small landholdings, that is the ordinary small gardens of ordinary houses where a few decades before the land might have been common land or otherwise in agricultural use or simply neglected prior to popular interest in gardening and the proliferation of public parks along with new technology (the lawn mower in 1837 as mentioned by /u/toothless_budgie in the linked older thread) made a good lawn a symbol of a well kempt garden. You may only have a square foot of land but by Jove if you keep that grasses on it looking good you can hold your head high.
The importance of a well kempt lawn was not merely aesthetic, it greatly improved the play of the lawn-games mentioned earlier and the history of English sport is closely intertwined with the history of English lawn maintenance.//
So what did cities have before widespread use of a lawn? With rural areas I'm guessing dirt, but in the cities was everything covered in bricks and concrete?
hi! although I don't believe this will address the question of swept yards, do check out this section of the FAQ (link on sidebar):