Tree-of-Heaven (Ailanthus altissima) is native to Asia, and began its journey west by being introduced to Europe in 1751 by a French Jesuit preist who brought it from Nanking, China to England. The first known specimen was brought into the United States a few decades later by William Hamilton, who planted this species in Philadelphia. People admired the beautiful foliage of these fast-growing trees, and for over a century have been planting it as an ornamental, although the leaves emit a foul-smelling odor.