During the 17th and 18th centuries coin collecting remained a pursuit of the well-to-do. But rational, Enlightenment thinking led to a more systematic approach to accumulation and study. Numismatics as an academic discipline emerged in these centuries at the same time as coin collecting became a leisure pursuit of a growing middle class, eager to prove their wealth and sophistication. During the 19th and 20th centuries, coin collecting increased further in popularity. The market for coins expanded to include not only antique coins, but foreign or otherwise exotic currency. Coin shows, trade associations, and regulatory bodies emerged during these decades. The first international convention for coin collectors was held 15–18 August 1962, in Detroit, Michigan, and was sponsored by the American Numismatic Association and the Royal Canadian Numismatic Association. Attendance was estimated at 40,000. As one of the oldest and most popular world pastimes, coin collecting is now often referred to as the "King of Hobbies".