Galway received a municipal charter from the crown in December 1484. This ensured the town's independence from the Clanrickard Burkes. At the same time, the creation of the wardenship of Galway gave the townsmen control of the large parish church, St. Nicholas' Collegiate Church.
Galway endured difficult relations with its Irish neighbours. A notice over the west gate of the city, completed in 1562 by Mayor Thomas Oge Martyn fitz William, stated "From the Ferocious O'Flahertys may God protect us". A bye-law forbade the native Irish (as opposed to Galway's Old English citizens) unrestricted access into Galway, saying "neither O' nor Mac shall strutte nor swagger through the streets of Galway" without permission.
During the Middle Ages, Galway was ruled by an oligarchy of fourteen1 merchant families (12 of Anglo-Norman origin and 2 of Irish origin), the 'Tribes of Galway. The city thrived on international trade. In the Middle Ages, it was the principal Irish port for trade with Spain and France. There is a legend of uncertain truth which claims that Christopher Columbus, on a trip to Iceland or the Faroe Islands, found signs of land beyond the Atlantic Ocean in or near Galway in 1477.2
The population of medieval Galway is thought to have been about 3000.

