In the mid 19th century, Siam was under threat from Britain and France. King Chulalongkorn (King Rama V, 1868–1910) could see that the continuing independence of Siam required modernisation. This required setting up a modern bureaucracy, professional armed forces and police, an independent judiciary with a modern law code, and full diplomatic relations with other countries. Slavery had to be abolished by peaceful, legal means, a public school system instituted, the Buddhist religious order reformed, and agricultural reforms promoted. Railways as well as modern financial and fiscal systems were also needed. King Chulalongkorn's intelligent and spirited pursuit of these reforms is the foundation of modern Thailand: he was entirely successful in keeping the country free of subjection to outside forces, the only south-east Asian country to do so. This is a historical development of the great importance, not to Thailand only: it provides an important example to all countries seeking to undertake post-colonial development.
The documents inscribed on the International Memory of the World Register in 2009 contain firstly, the official records of the state, especially the archives of the new Ministries established in 1892. Altogether these comprise 800,000 pages of documents, plus 367 bound volumes of judicial decisions, petitions and reports. Secondly, there are about 2,846 items of the King's private correspondence, notes and reports. Also included are volumes of the King's writings, poetry and prose. Among others are the letters he sent to his daughter while travelling abroad. The collection as a whole illustrates the times, the interests, and the important work and achievement of King Chulalongkorn.