The founders of New York’s Dia Art Foundation are suing the organization and Sotheby’s to stop the auctioning of artworks they say were donated with the intention of keeping them readily available to the public. Heiner Friedrich and his ex-wife, Fariha Friedrich, who started the foundation in 1974 with art historian Helen Winkler, filed the suit in the state Supreme Court in Manhattan on November 7, 2013.

The sale, which is scheduled to take place at Sotheby’s on November 13 and 14, includes contemporary artworks by Barnett Newman, Cy Twombly and John Chamberlain – all of which the plantiffs claim were donated or loaned to Dia in the 1970s and 1980. The Friedrichs said in their complaint, “Dia’s proposed auction of the subject works would remove the works from public access and viewing in direct contravention of Dia’s entire intent and purpose and of plaintiffs’ arrangements and understandings with Dia.”

The Friederichs started Dia to help artists bring “visionary projects” to fruition and to make them available to the public. Heiner Friederich has not served on the foundation’s board since 1985; Fariha remains a trustee emeritus. They have asked for a temporary restraining order and preliminary injunction to stop the sale.