Through a series of military and political moves, the kingdom of Silla (57 B.C–668 A.D.) achieves dominance over most of the Korean peninsula by the end of the seventh century. Its campaign of unification begins with the defeat of the Gaya Federation in 562; after an alliance with the Chinese Tang (618–906) court, it succeeds in conquering the kingdoms of Baekje in 660 and Goguryeo in 668. By 676, Silla forces Chinese troops to withdraw into Manchuria, and for the first time in history the peninsula comes under the sway of a single Korean government. In the succeeding Unified Silla dynasty (668–935), Korean culture flourishes, creating a political and cultural legacy that will be handed down to subsequent rulers of the country.

Consolidation of the three kingdoms under a single absolute ruler leads to an increase in the wealth of the aristocracy, whose status is secured by a rigid hereditary class system. Gyeongju, the capital of Unified Silla, is a prosperous metropolis with magnificent palaces and imposing Buddhist temples. Officially sanctioned as the state religion, Buddhism exerts a profound influence on the arts; some of the most refined and sophisticated Buddhist art and architecture in East Asia is produced in Korea during this period. The Unified Silla court maintains close relations with Tang China through trade and diplomatic exchanges. Throughout this period, Korea continues to play a crucial role in the transmission of technology and ideas to Japan.

Beset by power struggles between the court and the aristocracy, Unified Silla declines in the late eighth century. The rise of local military garrisons and landed gentry, coupled with increasing unrest among the common people, lead to a deterioration of the social fabric and the establishment of competing regional states. In 918, Wang Geon (877–943), a high-ranking military official, reunites the country under the new Goryeo dynasty (918–1392).

• 528 (552 according to an alternate tradition) Buddhism is officially recognized as the state religion by the kingdom of Silla. Although the religion has been known to the local society since the early fifth century through the activities of monks from the Koguryô Kingdom in the north, Silla, located in the far southeastern corner of the peninsula, is the last of the Three Kingdoms to sanction formally the practice of Buddhism.

• early 6th century By this time, all of Korea's rulers appear to be convinced—likely swayed by contemporary Chinese imperial examples—that the Buddhist religion has the potential for strengthening and safeguarding the nation. Throughout the peninsula, the increasingly close association of Buddhism and the state is signaled by the erection of temples and crafting of icons at royal expense. For example, in 527, the impressive Taet'ong-sa temple is built at the center of the Paekche capital, Ungjin (modern Kongju, South Ch'ungch'ông Province), in part as a diplomatic gesture intended to reinforce the kingdom's ties to a pious Chinese sovereign. Twenty-six years later, in 553, in the Silla capital of Kumsông (modern Kyôngju, North Kyôngsang Province), construction is initiated on Hwangnyong-sa, a royally endowed temple whose famous nine-storied pagoda (begun more than a century after the founding of the temple) comes to be revered as one of the protective talismans of the nation.

Korean Buddhist sculpture of the sixth century begins to show distinctive indigenous characteristics but also reflects the strong influence of Korea's diverse contacts with the artistic traditions of China and India.

Archaeological evidence indicates that, in an effort to buttress their temporal authority, the monarchs of Silla and Paekche continue to present themselves as possessing shamanic powers as late as at least the sixth century. The discovery of gold crowns of shamanistic design in the royal graves of both states suggests that the rulers who wore them sought the sanction of ancient indigenous religious belief, as well as Buddhism, for their governance.

• 538 The ruling monarch of Paekche, King Sông (r. 523–54), sends the official diplomatic mission that formally introduces Buddhism to the Japanese court. The mission presents to the court Buddhist images and sutras. Korean priests play an important part in the propagation of the religion in Japan during the second half of the sixth century, and the influence of Korean sculptors can be traced in Buddhist works of the Asuka period (538–710) from the Nara area.

• 553 Paekche's armies culminate a long campaign to regain the Han River valley—lost to Koguryô almost eighty years earlier, in 475—with victories in a series of costly assaults on Koguryô fortifications. Silla troops, arriving on the pretense of offering assistance, attack the exhausted Paekche army and take possession of the entire Han River valley. Incensed by this betrayal, Paekche's King Sôong in the following year launches a retaliatory strike against Silla's western border, but is captured and killed in the resulting melee.

• 562 Silla's seizure of the Han River valley is followed nine years later, in 562, by its forceful annexation of all the remaining territory of the Kaya Federation. A series of successful expeditions against Koguryô also brings a vast area along Korea's northeastern coast under Silla's control. Possession of the Han River valley provides Silla with unhindered access to the Yellow Sea and thus to China for the first time in the kingdom's history. Silla begins to dispatch frequent embassies to the Chinese courts. Initially, while China remains politically divided between its own contending northern and southern regimes, these missions serve largely cultural ends. After the Sui dynasty's (581–618) unification of China in 589, however, the significance of diplomacy for all northeastern Asian states changes abruptly, since the rulers of both the Sui regime and the succeeding Tang dynasty (618–907) are eager to take advantage of intrapeninsular rivalries. Korean solicitations for Chinese military assistance provide the rulers of unified China with a convenient pretext for attacks that are, in fact, motivated by the desire for Chinese territorial expansion.

• 598–614 With the encouragement of Silla and Paekche, the Chinese Sui dynasty mounts four massive but unsuccessful assaults upon Koguryô's borders.

• late 6th–mid-7th century Mural paintings from the Koguryô Great Tomb of Kangsô, in Sammyo-ri, Kangsô-gun, South P'yông'an Province, dated to the late sixth century, represent a second stage in the development of early Korean landscape painting. In contrast to the symbolic, graphic representations of mountains in the earlier fifth-century Koguryô tomb murals, the mountains depicted in these paintings are more realistic, with clearly defined spatial relationships between near and far peaks. The tripartite composition of a central mountain flanked by two smaller mountains, the suggestion of volume conveyed by the mountains' shaded contours, and the differentiation between rocky and earthen mountain forms all indicate an increased interest in landscape painting to portray real, tangible elements of nature rather than to serve as a symbolic setting for narrative elements.

In the first half of the seventh century, Korean landscape painting style undergoes yet another change, as exemplified by mural paintings in two Koguryô tombs in South P'yông'an Province—Nae-ri Tomb no. 1, in Shijok-myôn, Taegong-gun, and Chinp'a-ri Tomb no. 1, in Chunghwa-gun. The Nae-ri Tomb paintings, like those of the late-sixth-century Kangsô Tomb, feature a tripartite composition of a host mountain and two guest peaks, but the profile of the central mountain is steeper, conveying a greater sense of height. In addition, the trees along the mountain ridges are more realistically rendered, with clusters of leaves and curvilinear trunks. An even greater sense of movement is expressed in the tomb murals at Chinp'a-ri. The windblown trees, whose trunks, limbs, and leaves are described in detail, and the swirling clouds show the influence of Chinese painting style of the Six Dynasties period (220–589). What begins in Koguryô as a largely symbolic representation of landscape gradually moves, by the early seventh century, toward a view of landscape as a subject worthy of realistic portrayal in its own right.

There is little surviving evidence of a tradition of landscape painting in the southern kingdoms of Paekche and Silla. A notable exception are two earthenware tiles with landscape decoration, which are among a group of eight tiles excavated from a Buddhist temple site in Puyô, South Ch'ungch'ông Province, the last capital of Paekche. Dated to the first half of the seventh century, these tiles display in their decoration a technical and stylistic sophistication that evinces a long process in the development of landscape depiction prior to this time.

• 645–648 Emperor Taizong (r. 627–50) of the Chinese Tang dynasty (618–907), acting in response to Silla's pleas for aid, unleashes three attacks against Koguryô. These assaults, like those of the preceding Sui dynasty between 598 and 614, fail to subdue the northern Korean kingdom.

• 660 The Tang court and its Silla ally launch a coordinated invasion of Paekche, the Silla army advancing by land from the east and the Tang force striking by sea from the west. Paekche's defenses are quickly overwhelmed, and its reigning monarch is captured and taken to China.

• 668 The Tang-Silla allies, having spent the preceding eight years consolidating their hold over Paekche's domain, invade Koguryô. The campaign proves irresistible, and the northern kingdom, weakened by the earlier Sui and Tang assaults and by internal political dissension, is swiftly vanquished.

• 676 The broad-based peninsular effort under Silla's leadership to prevent Chinese domination of Korea succeeds in forcing Chinese troops to withdraw into Manchuria, in northeast China. For the first time in history, all of the Korean peninsula—excepting a narrow band in the north—comes under the sway of a single Korean government, known as the Unified Silla dynasty.

The largely conciliatory policies of Unified Silla's first kings toward their former foes, the defeated states of Paekche and Koguryô, and the establishment of an administrative structure for governing the whole country brings about a "golden age" of prosperity and peace, which lasts for nearly a century (ca. 675–765). The new government maintains close relations with Tang China and Japan through trade as well as diplomatic and scholarly exchanges. The peace that characterizes Unified Silla's external relations nurtures general prosperity throughout the country and the remarkable affluence of the capital, Kyôngju. Korean Buddhism, supported by the government as the state religion and lavishly patronized by the wealthy aristocracy, enters a phase of unparalleled institutional development, societal expansion, and scholarly achievement. Some of the most refined and sophisticated Buddhist art and architecture in East Asia is produced in Korea during the Unified Silla period.

• 698 A former Koguryô general establishes the new kingdom of Parhae (Chinese: Bohai), which encompasses most of the former Koguryô Kingdom's holdings in Manchuria. Although the relationship between the Parhae and Unified Silla courts is merely cordial at best, armed hostilities are avoided and the peninsula is spared any serious threat of aggression from the north until after Parhae's destruction by the Khitan, a seminomadic people of Manchuria, in 926.

• 7th–8th century During this period, two of the most influential sects in the history of Korean Buddhism, the Avatamsaka sect (Hwaôm) and the meditative tradition of Sôn (Chinese: Chan; Japanese: Zen) are introduced to the peninsula, transmitted by Unified Silla monks who go to study in Chinese monasteries.

• early 8th century The earliest known extant example of a block-printed text is a portion of a dharani (Buddhist charm) discovered in 1966 during the repair of a stone pagoda at Pulguk-sa (Temple of the Buddha Land), east of Kyôngju. The document predates the reconstruction of the temple in 751.

• 751–after 774 Construction of the famous cavelike granite sanctuary of Sôkkuram, on Mount T'oham east of Kyôngju, begins in 751 at the order of Prime Minister Kim Tae-song and is completed after his death in 774. The cave temple, one of the masterpieces of East Asian Buddhist art, consists of a rectangular anteroom and a circular main chamber with a domed ceiling, connected by a narrow corridor. At the center of the main chamber is a monumental stone image of the Buddha (over ten feet in height) seated on a lotus throne. Carved in relief and set into the walls and niches of the sanctuary are thirty-seven stone figures of bodhisattvas, disciples, and guardians. The magnificent image of the seated Buddha within the sanctuary faces the East Sea in the direction of Japan, an orientation that has given rise to the common belief that Sâkkuram was created, in part, to protect Korea from Japanese aggression.

Another major project undertaken at this time is the rebuilding of Pulguk-sa, originally founded in 553. Located in the foothills of Mount T'oham near Sôkkuram, it is Korea's oldest surviving Buddhist temple.

• late 8th–early 10th century Beset by power struggles between the court and aristocracy, Unified Silla goes into decline in the late eighth century. By the start of the tenth century, the Unified Silla monarch's claims to supremacy on the peninsula are openly contested by the self-declared kings of two short-lived regional states, Later Paekche (892–936) in the southwest and Later Koguryô (901–18) in the north.

• 918 The ruler of Later Koguryô is ousted by a group of his military commanders, led by Wang Kôn (877–943). Having assumed control of his former master's northern domain, Wang (also known by the posthumous title of T'aejo, or Grand Founder; r. 918–43) is proclaimed king of the new Koryô dynasty and establishes the capital at Songdo (modern Kaesông, North Korea). He succeeds in reunifying the peninsula by engineering the voluntary submission of the last of the Unified Silla monarchs in 935 and conquering Later Paekche in 936.

Buddhism continues to flourish under the patronage of the Koryô court and aristocracy. Temples increase in number, landholdings, and wealth, as well as political influence, over the course of the dynasty. Elaborate Buddhist rituals are regularly performed at public expense for the welfare of the state and at the behest of wealthy private devotees. The elegant, refined lifestyle of the court and upper classes is clearly reflected in the arts of the period. Exquisitely crafted bronzes, lacquerware, and celadon ceramic wares intended as devotional objects also reflect the increasingly personal nature of Buddhist religious expression. The production of Buddhist paintings and illustrated sutras reaches the highest level of artistic achievement in response to the demand of the court and aristocracy for images to serve as objects of worship.

Frequent official exchanges and trade with China, especially in the early part of the Koryô period, offer Korean artisans a rich array of new technologies and motifs, which they adapt and refine to accommodate native tastes. Early Koryô trade missions export gold, silver, ginseng, paper, brushes, ink, and fans to China, and import silk, ceramics, books, musical instruments, spices, and medicine. Further stimulus is provided by interaction with countries beyond East Asia, facilitated by the travels of Buddhist monks to and from India and the arrival of merchant seamen from the Middle East. Similarly, many Buddhist monks travel to China for lengthy periods to study religious doctrines and texts, which they bring back to Korea upon their return. Korean intellectuals pride themselves on their knowledge of China's classical literature and their ability to write and compose poetry in Chinese.

• 993–1018 The Khitan—the seminomadic tribe who founded the Liao dynasty (907–1125) and whose domain extends into northern China—organize three major invasions of the peninsula.