The king collected taxes on paddy land and on other sources of bounty such as fruit trees. Before the end of the Ayudhya period the government issued documents to the farmers showing how much land they farmed, how many mango trees they had, etc. These tax documents came to represent de facto proof of the farmers' land-holding right.(30) At least by the end of the Ayudhya period commoners exercised ownership rights in land as against other commoners; they bought and sold land, devised and inherited land and borrowed against it. But if a farmer did not make beneficial use of his land, he lost any claim he had to that land.(31) As Lingat points out, this "use it or lose it" policy helped to maximize land tax revenue, an important financial resource throughout this period.(32)
Thus throughout the Ayudhya period (about 1350-1767) and during the period leading up to the Anglo-Siamese treaty of 1855, farmers' rights in the land they tilled gradually increased. By the dawn of the modern era farmers exercised virtually complete ownership rights over their land. But the legal system, which was based upon the thammasat (natural law) and recognized the king as the divine embodiment of law, held the king to be owner of all land. Certainly this legal fiction represented no threat to the farmer's tenure by 1855.(33) If political and economic events had been different after 1855 perhaps the Thai legal system might have developed its own distinctive approach to the "use it or lose it" problem. But, as the next section of this chapter shows, the events of the second half of the nineteenth century forced Thailand to adopt many western ideas, including a European legal system and a western theory of title. The Thai farmer's ancient usufructory right was further refined, but was then pushed to the periphery.