The post-Angkor period of Cambodia (Khmer: ប្រទេសកម្ពុជាក្រោយសម័យអង្គរ), also called the Middle period, refers to the historical era from the early 15th century to 1863, the beginning of the French protectorate of Cambodia. As reliable sources (for the 15th and 16th centuries, in particular) are very rare, a defensible and conclusive explanation that relates to concrete events that manifest the decline of the Khmer Empire, recognised unanimously by the scientific community, has so far not been produced. However, most modern historians have approached a consensus in which several distinct and gradual changes of religious, dynastic, administrative and military nature, environmental problems and ecological imbalance coincided with shifts of power in Indochina and must all be taken into account to make an interpretation. In recent years scholars' focus has shifted increasingly towards human–environment interactions and the ecological consequences, including natural disasters, such as flooding and droughts.
Stone epigraphy in temples, which had been the primary source for Khmer history, is already a rarity throughout the 13th century, ends in the third decade of the fourteenth, and does not resume until the mid-16th century. Recording of the Royal Chronology discontinues with King Jayavarman IX Parameshwara (or Jayavarma-Paramesvara), who reigned from 1327 to 1336. There exists not a single contemporary record of even a king’s name for over 200 years. Construction and maintenance of monumental temple architecture had come to a standstill after Jayavarman VII's reign. According to author Michael Vickery there only exist external sources for Cambodia’s 15th century, the Chinese Ming Shilu ("Veritable Records") and the earliest Royal Chronicle of Ayutthaya, which must be interpreted with greatest caution.
