In 1936 the author, politician and garden designer Harold Nicolson bought four, round antique altars and a Corinthian capital from the sale of Shanganagh Castle, Co Wicklow. Nicolson and his wife, Vita Sackville-West, placed these marbles in a garden compartment at Sissinghurst that was intended to evoke the landscape and antiquities of the Cycladic island of Delos. These are among the most important antiquities in the collections of the National Trust, yet their provenance and significance has been obscured by their presumed status as ‘mere’ ornaments to the celebrated gardens at Sissinghurst Castle. This paper traces the provenance of this group of antiquities back to Delos and their discovery by a hero of the Greek War of Independence. Historic context for Vita and Harold’s use of the altars as adornments to their garden will be examined in the context of earlier use of similar Delian altars in earlier garden design – the seventeenth-century ‘garden museum’ at Arundel House, Strand, London, or the eighteenth-century gardens at Wrest Park. Finally, entry of the Sissinghurst altars into British collections will be examined through a political lens and through Nicolson’s philhellenism.