This is a wonderfully detailed, colourful, 1615, picture of the splendid court procession through Brussels, during which Archduchess Isabella was made Queen of the Crossbowmen's Guild. It rather puts one in mind of the annual Brighton Pride parade, but with horses!
Above is a detail from the painting which is nearly 4 metres long.
The Ommeganck is an exhibit in the Theatre & Performance Galleries. These contain an intriguingly varied collection of theatrical material. This includes hand-operated sound-producing machines donated by Brighton's Theatre Royal, obviously now rendered obsolete by the introduction of synthesisers and electronic sound reproduction.