In the 1600s, cotton and silk fabrics that bore colorful and exotic printed patterns, known as “calico,” were flying off the shelves of the East India Company's stores. The rapidly escalating demand for calico had taken a visible toll on the European textile businesses. The trend spread across Europe and North America, and picking cotton was such an arduous task that even when relying almost entirely on slave labor, it was hard to make cotton a profitable industry in North America. That all changed with Eli Whitney's invention of the cotton gin near the end of the 18th century. Able to more effectively separate the cotton fiber from seeds, Whitney's cotton gin turned the cotton industry into one of the antebellum South's biggest cash cows, and as a result, the region became even more dependent on slave labor than before. The cotton gin exponentially increased the labor output, which in turn brought an exponential increase in the number of slaves throughout the South, despite the fact the international slave trade was banned in the fledgling United States in the early 19th century. By the dawn of the Civil War, there were over 3 million slaves in the South, and cotton was so crucial to the Southern economy that the Confederacy would try to compel European countries to intervene on their side by refusing to export cotton to them. The Industrial Revolution's changes also meant mass production was taking hold on both sides of the Atlantic, and Whitney's principle of interchangeable parts was put to good use not only by the inventor himself, but by several other progressive business executives. After inventing the cotton gin, Whitney had won several lawsuits against farmers for non-payment by suing their states, and with an amassed figure of $90,000, he was able to start additional businesses. When war with France seemed like it was looming and the national armory could only produce 1,000 muskets in three years, Whitney intervened.