At the turn of our era, and in circumstances that remain obscure, orthodox Brahmanic circles set up a cosmological system, that of the four "ages"(yuga), which nothing would ever replace in the Indian imagination. The system finds mature expressions as early as the famous Laws of Manu(Manusmṛti, 3rd century), certain recent sections of the Mahābhārata (3rd century?) and the earliest layers of the Purāṇa ("tales of antiquity", 3rd-4th century). According to this conception, every cosmic "microcycle" (a period of around twelve thousand years) is made up of four successive ages, from the "golden age"(kṛtayuga) to the "age of discord"(kaliyuga ;the nomenclature of the four ages is borrowed from that of the dice game, from winning move to losing move), itself punctuated by a yugānta or end of the last age. In its purely cosmological appreciation, this quaternary model is limited to a description of the religious (above all ritual), moral, intellectual and physical degradation of mankind. However, the device soon provides a framework for Brahman eschatology and feeds apocalyptic predictions, most of which can easily be interpreted as ex post facto prophecies describing a socio-religious, moral, political and economic environment in crisis. Pregnant girls, excessive imposition of Brahmins, impious kings, an explosion of heresies, foreign yoke, inversion of the seasonal cycle, mixing of castes, unfaithful women and other infamies abound.
One might think that Indian Buddhism was entirely foreign to this double cosmological and eschatological device. At such a time, it had a sophisticated cosmology that foresaw the end of eons scarcely less terrifying than their Hindu counterparts. Buddhist dogma states that when human life is less than a hundred years old, five degradations or corruptions(kaṣāya, more literally "oxidations", which perhaps explains why the monks' "rusty" robes bear the same name) will affect human society: a shortening of the lifespan, then, but also a sharpening of passions, the outpouring of "false views", moral decay and the general degradation of living conditions under the species of famine, disease and war. While the motif of the five corruptions has dominated apocalyptic rhetoric throughout Asia to this day (for example, it served as a key to the 13th Dalai Lama's interpretation of the Soviet occupation of Mongolia), it is not the center of gravity of Buddhist eschatological fears and expectations, rather, these revolve around the belief in the "disappearance of the good law"(saddharmavipralopa), a "millenarian" scenario in the sense that Buddhism will disappear some 500, 1,000 or 5,000 years after the definitive extinction (the parinirvāṇa) of Buddha Śākyamuni (circa 400 BC). This is the scenario that will provide the framework and main motifs for Buddhist apocalypticism, which will explain the decline of the good law in terms of the founder's unintelligent readings, disinterest in salvation practices, internal quarrels, immorality, lax discipline, wives, livestock and simony.
This begs the question: what led seemingly well-equipped Buddhists to resort ever more fully to the eschatological repertoire of their Brahmin competitor? An analysis of several sources preserved in Sanskrit and/or Tibetan reveals a growing presence of Kaliyuga in Buddhist literature. Admittedly, this repertoire does not shy away from polemics and good-natured irony. The Brahmins of Kaliyuga , for example, are criticized for justifying their taste for meat and related ritual violence with theological-sacrificial imperatives; or for legitimizing their caste privileges (monopoly over the sacred economy, ritual, the afterlife and scholarship) with mythological, scientific and philosophical considerations. Elsewhere, however, Buddhists do seem to resort to the Kali age to give voice to their concerns about the rise of śivaism in 6th-7th-century India and beyond(Kāraṇḍavyūhasūtra), armed conflagrations likely to result in the destruction of their religion(Laṅkāvatārasūtra), and finally, around the eleventh century, the Mohammedan peril - already him(Kālacakratantra). During the second half of the first millennium, Buddhists composed versified apocalyptic sermons entirely centered on kaliyuga(Kaliyugaparikathā). Lastly, where traditional dogmatics did not expect Buddhas to preach in the midst of the five corruptions (Sarvāstivāda), the Great Buddhist Vehicle no longer hesitates to measure the compassion of Buddhas by their readiness to teach in the midst of said corruptions(Saddharmapuṇḍarīka, Sukhāvatīvyūha, etc.), identified for the time being with kaliyuga (Karuṇāpuṇḍarīka, but also Abhidharmakośabhāṣya).
This Buddhist appropriation of kaliyuga eludes any unitary explanation. It reflects polemical imperatives as well as the anxieties of milieus about which, in ancient India at least, we know nothing, including their location in time and space. Perhaps it's not too much of a mistake to invoke the possible "popularity" and plasticity of the rhetoric associated with the yugas, represented early on, albeit without detail, in epigraphy. Less closely linked to dogma and therefore doctrinally more flexible, the kaliyuga may have seemed both a more open representation and better able to strike a chord. We hope that future research will enable us to articulate or superimpose apocalyptic prophecies and historical configurations, as is the case with Tibet, Khotan or the Sino-Japanese world. In any case, this appropriation forms a singular chapter in the long and complex history of interactions between Brahmanism and Buddhism.