Please note: Modern ball dress or everyday dress is not appropriate for this event!
This is a good opportunity to wear Renaissance costume, or period costume from medieval to early baroque/Stuart. If you don't have a costume, have a look at the links below (mostly in English) - contemporary dress can be easily adjusted to make a Renaissance-like outfit! Please avoid high heels, they are not suitable for Renaissance dance.

 →   Renaissance at www.marquise.de
 →   www.elizabethancostume.net
 →   Le Poulet Gauche  -  In the Kitchen and Market: Pictures of Ren. low-class people
 →   The Renaissance Tailor - look for "Accessories" in the menu!
 →   A gable hood, transforms your long, plain dress into a Renaissance ladies' robe!
 →   Another gable hood
 →   Renaissance hats and caps
 →   More hats
 →   Instant Breeches, wear them with a wide shirt and Ren. cap!
 →   More from the wunderful "Sempstress"
 →   A lady's gown  of the Italian Renaissance, free online pattern and construction method

and:
 →   Costumes throughout history, links and resources for fashion from the Middle Ages to 20th Century