Pembrokeshire is packed with really interesting relevant history (besides castles).
However,

As far as Westgate Chapel Website is concerned, the obvious point of history is the witness of the fellowship at Westgate Chapel AND the enormous Pembroke Castle, just outside our doors.

As you are likely here on holiday you are probably not particularly interested, the history of Westgate. If you are, you can find out particular details in the section “Why US” and the sub-section “History”.