Complex sentence: The first competition to be a negotiate a sponsorship deal was the League Cup, negotiating a deal in 1982 with the Milk Marketing Board, and it became known as the "Milk Cup" and has since adopted the name of its sponsors in this same way.
Split into simpler sentences: The first competition to be a negotiate a sponsorship deal was the League Cup, negotiating a deal in 1982 with the Milk Marketing Board. It became known as the "Milk Cup" and has since adopted the name of its sponsors in this same way.