vintage Union made brown and cream floor length strapless dress - This is Yours

Possibly from the 1970s or 1980s this is a Union made floor length strapless dress in chocolate brown and cream - it’s absolutely stunning! The ties confuse me. There’s a long tie and a short tie. And there’s a loop on each side seem. So I laced the longer string through the loops and criss crossed and tied at the neck. Besides the ties being confusing, this dress is to die for! Marked a size 11. Pit to pit is approximately 14” lying flat. Overall length is 55”