The history of Spain dates back to the Early Middle Ages. In 1516, Habsburg Spain unified a number of disparate predecessor kingdoms; its modern form of a constitutional monarchy was introduced in 1813, and the current democratic constitution dates to 1978. After the completion of the Reconquista, the kingdoms of Spain were united under Habsburg rule in 1516. At the same time, the Spanish Empire began to expand to the New World across the ocean, marking the beginning of the Golden Age of Spain, during which, from the early 1500s to the 1650s, Habsburg Spain was among the most powerful states in Europe.Written in an engaging style, Mary Parmele's concise study A Short History of Spain introduces readers to the key themes that have shaped modern Spain.