Complex sentence: George Davies was the first player to graduate from Llandeilo RFC to be play for his country, for he joined Swansea RFC in 1898 and became a Welsh international in 1899-1900, winning three caps against England, Scotland and Ireland during that season.
Split into simpler sentences: George Davies was the first player to graduate from Llandeilo RFC to play for his Wales. He joined Swansea RFC in 1898 and became a Welsh international in 1899-1900, winning three caps (awarded for playing at an international level) against the other home nations during that season.