Severely threatened by the western colonialism ,The king made the considerable reforms in political and social structure to ensure the country 's independence (His great contributions included the abolition of slavery and old custom , promotion of modern education to people,Reform of the legal system to be at the western standard, expansion of the communication system through the construction of roads and railway, and by establish of post, Telegraph and telephone services as well as electricity and water works and medical services, social work and public utilities) (established friendly relation with the western countries. the king traveled to Europe twice to build the relationships with the major powers) (set up modern army and forts to protect the country agreed to cede some parts of territory to French to save most of siam territory)