For those of Welsh descent, the English surname system has its origin with the Act of Union. Many surnames appear around, and after, this Act was put into affect. The following figure presents the impact on the JONES surname as it appears in the "List of Early Chancery Proceedings" preserved in the Public Record Office, England.
It was after 1544 that the JONES surname starts to appear in the legal records. By 1558, the surname peaks and begins to climb again after 1650. Other surnames from Welsh families had the same origin. The next figure demonstrates how different surnames came into existence.
In each case, the individuals shared a common ancestor [Thomas]. Each "son" in the Welsh naming system would become "Richard ap Thomas", "Edward ap Thomas", "John ap Thomas", and "David ap Thomas". When the Act of Union took affect [1536 - 1542], "Peter ap Richard ap Thomas" became "Peter Richards", and "David ap Edward ap Thomas" became "David Edwards". Any who were the "son of a John" became "JONES". On and on it would go. After several generations of different surnames, the family often lost their Welsh connections. So, a different surname took a distinctive branch along the family tree although they shared a common grandfather. For the genealogist, this process is important in recognizing that today, those who share the same surname, may not be related at all.