The May jaunt, a pageant celebrating the "joli mois de Mai" when one had to wear green garments known as livree de mai... (https://web.archive.org/web/20060610070441/http://humanities.uchicago.edu/images/heures/heures.html) See how some of the characters have donned crowns of greenery, and the ladies wear light green dresses. As was the case for April, the man in the ample gold-embroidered blue robe seems to be the Duc de Berry himself in his youth. I suspect the lady on a white horse at the center of the composition is the bride to whom he was betrothed in that picture. Does she not look like the same young woman? In the background, we recognize the towers of the Conciergerie and the Tour de l’Horloge in the Isle of the Cité, as they still exist to this day. This was the skyline of Paris in the late Middle Ages. Above this lovely scene the signs of Taurus and Gemini dominate the month of May. (http://blog.catherinedelors.com/may-from-les-tres-riches-heures-du-duc-de-berry/)