One of the most frequent truisms in relevant Hungarian studies is the presence of endless swamps in the pre-modern Carpathian Basin. The extent of swamps and marshes along the rivers was, however, reduced in the modern period, mostly in the one and a half centuries from the 1780s onwards, due to large water control projects that have been interpreted in the scholarly literature ever since as masterpieces of engineering. These in the first half of the nineteenth century, the so-called Reform period. Researchers assumed that because the Ottomans made no effort to manage water, areas that before their presence had been suited to growing grain or other commercial crops became temporarily covered by water at the beginning of the eighteenth century, with large areas becoming wastelands with no potential income connected to them. This rather simplistic view was largely based on a map made in the 1930s by Woldemár Lászlóffy, one of the most respected hydrologists of twentieth-century Hungary. His map, published in 1938, entitled “Water-Covered Areas and Wetlands in the Carpathian Basin Before the Beginning of Flood Protection and Drainage Works” (A Karpat medence vizboritotta es arvizjarta teruletei az armentesitő es lecsapolo munkalatok megkezdese előtt; see Fig. 2.1) heavily overestimated the areas that were recurrently covered in water before the beginning of the above-mentioned drainage works.