Complex sentence: It was established in 1928 as an independent organization, becoming a branch of the newly-formed Society of Architects in Wales (as the RSAW was initially styled) in 1970 upon the restructuring of the Royal Institute of British Architects (RIBA).
Split into simpler sentences: It was established in 1928 as an independent organization, becoming a branch of the newly-formed Society of Architects in Wales (as the RSAW was initially styled) in 1970 upon the restructuring of the RIBA. The RSAW is the Wales region of the Royal Institute of British Architects (RIBA).