Amazing condition - Oleg Cassini Silk Shift Dress Black with fun Sequin Embellishments. Three-Quarter Sleeve with Scoop Neck. About the designer: Oleg Cassini, Inc. is an American fashion house founded by American fashion designer Oleg Cassini. The company is based in Oyster Bay Cove, New York, and was established in 1951. His designs were known for their clean but feminine aesthetic. Fame would come quickly when he was chosen to be the “Secretary of Style” to first lady, Jackie Kennedy.