During the reigns of King Mongkut, King Rama IV (1851??8) and King Chulalongkorn, Rama V (1868??910), the vast majority of Siamese were rice farmers who employed simple methods and rudimentary tools to work the fields. Nevertheless, harvests were bountiful due to the climate and fertile soil, and many farmers were able to produce three harvests per year. Prior to the kings' modernisation drive, Siam's farmers had to give one-quarter of their rice harvest to the king as tax. To ensure the entire population was well fed, Siam had a law that only when three year's supply of rice was stocked, would the country export the product. Similar state monopolies existed for other foods.