The compromise accord , which was initially reached in May at a meeting in Athens between the museum 's director , Michael Brand , and the Greek culture minister , Georgios A. Voulgarakis , provides for the return to Greece of a large stele , or grave marker , acquired by the museum in 1993 , and a small marble relief from the island of Thasos bought by the museum 's founder , the oil magnate J. Paul Getty , in 1955 .