In what era were family or surnames first deemed necessary and who decided on a family name?

The introduction of family names depended to some extent on social factors. The 'high and mighty' took on family names much earlier than the rest of the population. People who didn't move around much were also less likely to need family names than those who travelled a lot. In England and Wales there was legislation in the reign of Henry VIII (reigned 1509-1547) requiring all parishes to maintain and preserve registers of baptisms (and dates of birth), marriages and deaths. It seems that it was at this time that ordinary people adopted surnames. In England and Wales the family chose its own name. This was often an occupation (such as Baker, Cooper, Carpenter, Smith) or based on the father's name (Johnson, Williamson, Harrison, Thom(p)son, etc.) or based on placenames. Provided nobody was trying to deceive or pretend to be an aristocrat there was no objection to families choosing their own names. NOTE. Family names that end in -s (instead of -son) are generally Welsh (or of Welsh origin) - for example, Jones (instead of Johnson), Thomas (instead of Thompson), Harris (instead of Harrison).