Medieval market of Jaca Activity · Jaca, La Jacetania, Huesca Image of Jaca, not of the place itself. The Mercado Medieval de Jaca is held at the end of September, coinciding with the veranillo de San Miguel (Saint Michael's little summer), as part of the festival 'Jaca, Reino y Leyenda', with jousts, historical re-enactments and craft stalls in the main squares of the historic centre; it draws tens of thousands of visitors each year. Photo: Juan Carlos Gil (CC BY-SA 3.0) What to see and do in Jaca