One highlight is the second gallery, packed with large maiolica vases that marked engagements, especially in Rome, and large plates made especially for wedding feasts.
The party also marked her engagement to David Bradby, a student at Oxford who became a pioneer of theatre studies.
The ring, with a frame of enormous diamond baguettes, was a far cry from the Zuni coral and turquoise bracelet the couple marked their engagement with in the mid-1970s, when they lived on tribal reservations in Arizona, but their collecting skill may be derived in part from those days, when they would buy craft work from Navajo and Apache artisans.
Dr John Paul, a microbiologist who has worked with Dumitriu for almost a decade, is aware of collaborations between fellow clinicians and artists that have not proved as fruitful: "I have seen people scrabbling around to tick the box on the funding form marked public engagement.
Boldness, enterprise, and dating to match those of Hannibal, constituted his tactics, and marked his engagements.
Look on each package for the right timing, and mark your engagement calendar.
Eugenie, like her elder sister Beatrice, is "very real", she insisted in a Vogue interview to mark her engagement.
In 1664, King Philip IV of Spain gave it to the Infanta Margarita Teresa to mark her engagement to Leopold I of Austria; in 1722, the diamond passed to the Wittelsbachs, members of Bavaria's ruling house.
Whistles has also benefited from the Kate effect after the duchess wore one of its white silk blouses in the series of Mario Testino photos taken to mark her engagement.
The party in April to mark his engagement to Glebova, a Canadian of Russian descent who was Miss Universe in 2005, was a media scrum of Beckham-esque proportions.
