 At a by-election in 1966, Gwynfor Evans won the parliamentary seat of Carmarthen, Plaid Cymru's first Parliamentary seat.The next year, the Wales and Berwick Act 1746 was repealed and a legal definition of Wales and of the boundary with England was stated.By the end of the 1960s, the regional policy of bringing businesses into disadvantaged areas of Wales through financial incentives had proven very successful in diversifying the industrial economy.