The data presented here were extracted and computerised by Mrs. Wendy Bellany and Mr. Julian Kemper, from microfiches of the census records from South Wales for 1851 and 1891.  Whilst it is not possible to answer the question 'who is a Jew', an attempt has been made to extract the data for those thought to be Jewish or who might have been.  There are two problems.  Firstly, because of its religious and ethnic background, the 'native' Welsh population often have biblical surnames.  Indeed, some place names in Wales are biblical.  Sometimes this can be dealt with by studying the given names, the country of origin, or even the trade.

Biblical names were so well respected by the population at large that there were cases of Jews changing their surnames to Isaac or Jacob because it was good for business.

Secondly, the ports of Swansea and Cardiff attracted many foreign seamen who might have been resident there on the day the census was taken.  Also, there were 'foreigners' involved in occupations ancillary to the ports or the large steelworks of the region.  An attempt has been made to include reasonably possible cases, sometimes on the basis of head of household only.

The 1891 Census required more information to be gathered than the 1851 census.  The spoken language information should be treated with caution.  Often English was recorded as the spoken language when it was not.  Jewish or Hebrew are listed where the correct statement would have been Yiddish.

Many Jews at the end of the 19th century, were tinkers travelling up the valleys to sell the housewives every day goods.  It was, for example, difficult for a housewife even to buy a needle.  They also went to the country town markets.  It is possible that some were away from home on the census day.  It is not likely that many had permanent residences in some of the remote places that have not been covered here.