In the following years, the Lewis and Mellon families proposed major donations from their extensive private collections, and helped provide the funds to house them. In December 1985, the museum opened its fourth addition, the square foot West Wing. The architects, Hardy Holzman Pfeiffer Associates of New York, were chosen by the Lewises based on their appreciation of the firm's 1981 design for the Best Products headquarters building north of Richmond. The wing now houses the collections of these two families.