This original lithograph, signed and inscribed, is number 9 out of an edition of 60 made by the artist for The Curwen Studio in 1971, apparently four years before the lithograph, called [possibly erroneously mistitled] Aegean Suite (1975) numbered 18/60, also from the Eric and Jean Cass collection and now in Brighton Art Gallery. Delos (1971) also forms one of 9 screenprints from The Aegean Suite (sets at Tate, given after artist's death and at the Pier Arts Centre, Stromness, from the collection of its founder Margaret Gardiner (1904-2005) with whom Barbara had visited Greece in 1954 after the death of her eldest child, Paul; editions not numbered). They were purchased by the Cass's together and catalogued in 2003 as if a pair. Aegean Suite (1975) is actually the same motif as the screenprint called December Forms (1970) which forms part of a series of 12, not numbered, made for Marlborough Fine Art (sets at Tate, given after the artist's death and The Pier Arts Centre, Stromness) called Opposing Forms.