After the transition of the Central-Javanese to the East-Javanese period the Borobudur temple slowly started to fall in decay. Today the height of the temple is 113.5 meters, yet during the time of the monument’s first large scale reconstruction works (1907-1911), the total height was only 31.5 meters tall. This reconstruction was carried out under supervision of the 33 year old Theodoor van Erp (1874-1958), to whom the V.O.C. Governor-General Rosenboom had assigned this task.
In the years of the reconstruction work Van Erp lived with his family at the slopes of the Borobudur. Due to his prior knowledge of art and construction techniques in Central-Java, Van Erp successfully managed to complete the reconstruction works within five years time. He had prepared the building plans already in 1902; part of the plans was to enhance the temple’s water draining system, to carry out some urgent reparations as well as a few partial restorations. Before they actually could start the construction project they first had to excavate the lower terraces; it took them seven months to dig these up. Next, the essential construction aspects could be taken into consideration, for they did not intend to replicate the cultural and religious aspects that are connected with the Borobudur, therefore allowing them to leave out certain details in the design so that they instead could focus mainly on the reconstruction of the key aspects that make the monument so special: its architecture and symbolism.
The reconstruction works carried out by Van Erp are considered successful even to this day; his efforts regarding his work at the Borobudur are still admired by many. Though in fact some traces of his works remain visible today, yet many believe that if compared to the monument’s condition prior to its reconstruction, then these minor aspects just cannot outweigh the truly astonishing results achieved by Van Erp. However, because Van Erp had deliberately chosen not to repair certain aspects some of these parts fell in further decay and deteriorated to a critical condition. Moreover, after some time had passed, a few earlier problems (like vegetation overgrow and recurring drainage issues) seemed to re-appear once again. Furthermore, later also a new problem arose; the increase of tourism brought along with it a range of security issues, because due to the many narrow paths and multiple terraces it was practically impossible to guard all areas in the temple complex. Thus, it was felt that in order to reduce several of these problems this required the use of technological equipment. And so, in 1955, the Indonesian government informed the UNESCO about the plans. Finally, in 1967, after several reports on the Borobudur’s condition had been conducted, meanwhile the problems remained and in some instances even worsened due to earthquakes, Indonesia formally requested financial aid from the UNESCO.
The UNESCO set up the ‘Save Borobudur’ project (Proyek Restorasi Candi Borobudur) through which funds were obtained from the contributions of the countries that participated in the project. The project was officially launched on 10 August 1973, followed by the actual restoration which started in 1975. The plans were to repair the drainage system once more, and to cleanse the reliefs. Yet even more drastic were the restoration of the walls and the reconstruction of the foundation. In order to do this they decided to remove certain parts of the Borobudur so that these could be cleansed and reinforced, after which these parts could be placed back in place again. Since this process required a considerable long time to complete, it allowed the necessary time for reinforcement of the foundation with ferroconcrete. And in order to prevent future damage of humidity from happening, they installed hygrometers within the construction of the Borobudur itself, which made it possible to timely and adequately anticipate on environmental changes.
All of the aforementioned measurements show the importance of technological equipment in the reconstruction of the Borobudur, something which prior to this project was yet unknown in other reconstructions in Central-Java. Partially because of the available technological equipment, combined with the necessary financial means, this large scale reconstruction finally could be successfully completed in 1984. Once completed, the Borobudur was put on the World Heritage List.
 Kempers, Bernet A.J., 1978: ‘Herstel in eigen waarde: Monumentenzorg in Indonesië”. De Walburg Pers; p. 65.
 Partial restorations, because at the time, apart from financial restrictions, a complete restoration was considered impossible since this would involve a whole lot more than just reparations alone. Only later, during the second stage of the restoration (which had begun in 1908) they shifted their plans somewhat and attempted to reconstruct the Borobudur as close as possible to its original state, but even then no complete restoration could take place because of the many missing pieces of original materials, as well as the lack of manpower needed to fulfill the large scale task.
 Kempers, Bernet A.J., 1978: ‘Herstel in eigen waarde: Monumentenzorg in Indonesië‘. De Walburg Pers; on p. 77 where he is called “The Man of the Borobudur”.
 Kempers, Bernet A.J., 1978: ‘Herstel in eigen waarde: Monumentenzorg in Indonesië‘. De Walburg Pers; p. 215.