what was the law about?
Basically it was a system to deal with beggars and vagrancy.
English Poor Laws
The origins of the English Poor Law system can be traced back to late medieval statutes dealing with beggars and vagrancy
who made changes in old laws preventing the rich from taking from the poor UNANSWERABLE in which place did the  english poor laws exist? England and Wales. between which years did this law prevail for? Roughly from 1536 to about 1967.
wiki:19557144
English Poor Laws [SEP] Tudor Poor Law
The origins of the English Poor Law system can be traced back to late medieval statutes dealing with beggars and vagrancy, but it was only during the Tudor period that the Poor Law system was codified. Before the Dissolution of the Monasteries during the Tudor Reformation, monasteries had been the primary source of poor relief, but their dissolution resulted in poor relief moving from a largely voluntary basis to a compulsory tax that was collected at a parish level. Early legislation was concerned with vagrants and making the able-bodied work, especially while labour was in short supply following the Black Death.