Towards the end of the first millennium there was a law requiring every Welshman to know the names of nine generations of his antecedents (this was to help to determine such things as land-ownership) and it is thought that every native of Wales could recite their ancestral tree for at least six generations.
For many decades in Wales surnames were not used; instead the names of past generations were linked by 'ap' or 'ab', meaning 'son of' and 'verch' or 'ferch', meaning 'daughter of'. Thus, for example, the wife of Owen ap Meurig (see tree on next page) was Eleanor (or Ellin) verch Robert ap Meredydd ap Hwlkin Llwyd ap Tudur Goch, etc. Occasionally a second name was added to help to distinguish one individual from another or to indicate a title. For example, Iorwerth Ddu ap Iorwerth ap Gruffydd ap Iorwerth ap Meredydd ap Methusalem ap Hwfa; 'ddu' means 'the black'.
You can find information about the Owen name in the first section of this site.
The tree on the next page does not show all the children of a marriage though a few noteworthy siblings are included. There is some uncertainty concerning the dates of early events and early names have been given a variety of alternative spellings, some of which are shown on the tree to aid further research.