5
The Bubonic Plague
External to the bulb market, one extraordinary event in the period 1634–1637 may have driven the speculation. From 1635 to 1637, the bubonic plague ravaged the Netherlands, killing 17,193 people in Amsterdam alone in 1636 (one-seventh of the population). It also caused 14,502 deaths in Leiden in 1635 (33 percent of the 1622 population); and it killed 14 percent of the population of Haarlem, the center of the tulip speculation, from August to November 1636, the moment when the trading in common and cheap varieties took off. The plague had marched westward with the dynamics of the armies in Germany starting in 1630.8 Plague also broke out from 1623 to 1625, from 1654 to 1655, and from 1663 to 1664, killing in Amsterdam oneninth, one-eighth, and one-sixth of the population, respectively. Van Damme (1976) quotes C. de Koning, who states that the plague began in 1635 and forced the city authorities to take drastic health measures:
