On 15 March 1526, the exchange took place at the border between Spain and France. Francis almost immediately repudiated the treaty and the eight-year-old Dauphin and his younger brother Henry spent the next three years as captives of Charles V, a period that scarred them for life. The Dauphin's "somber, solitary tastes" and his preference for dressing in black (like a Spaniard) were attributed to the time he spent in captivity in Madrid. He also became bookish, preferring reading to soldiering.