Understanding the historical context often helps the genealogist uncover a variety of factors associated with the family tree. These factors may provide hints as to the direction ones tree climbing will take.
For those of Welsh descent, this context is frequently framed by war.
The book by Philip Warner outlines a span of some three thousand years. From prehistoric times to the battle of Fishguard ( 22 Feb. 1797) the topic is organized by a major theme. "The Battles against the Romans", "The Battles against the Normans", and "The Battles of the Civil War" are just a few of the chapter headings. Ordnance Survey maps allow for battle site identification.
For me the most helpful was a list of Welsh at the battle of Agincourt. (Appendix 6, pp. 147 - 149)
It is like skipping rocks in a historical pond of Welsh history. Come skip a few.
The book was published by Barnes & Noble, Inc., 1977, and again in 1997.