Silla, also known as Shilla, was one of the ancient Korean kingdoms that existed from 57 BCE to 935 CE, primarily located in the southern and central parts of the Korean Peninsula. Together with Baekje and Goguryeo, they formed the historical Three Kingdoms of Korea. Of these, Silla had the smallest population, approximately 850,000 people, which was notably less than Baekje's 3,800,000 and Goguryeo's 3,500,000.^[38] Founded by Hyeokgeose of Silla from the Park family, the kingdom saw dominance by the Gyeongju Kim clan for 586 years, the Miryang Park clan for 232 years, and the Wolseong Seok clan for 172 years. Silla initially began as a part of the Samhan confederacies and later allied with China's Sui and Tang dynasties. It eventually unified the Korean Peninsula by conquering Baekje in 660 and Goguryeo in 668. Following this, Unified Silla governed most of the peninsula, while the north saw the emergence of Balhae, a successor-state of Goguryeo. After a millennium, Silla divided into the Later Three Kingdoms, which later transitioned power to Goryeo in 935.^[39]

The early history of Silla traces back to the Proto–Three Kingdoms period, during which Korea was divided into three confederacies named Samhan. Silla originated as "Saro-guk", a state within the 12-member confederacy called Jinhan. Over time, Saro-guk evolved into the Six Clans of Jinhan from the legacy of Gojoseon.^[40] Korean historical records, particularly the legend around the founding of Silla, tell of Bak Hyeokgeose founding the kingdom around present-day Gyeongju in 57 BCE. An interesting lore recounts Hyeokgeose being born from an egg laid by a white horse and being crowned king at the age of 13. There are inscriptions suggesting the royal lineage of Silla had links to the Xiongnu through a prince named Kim Il-je, or Jin Midi in Chinese sources.^[41] Some historians speculate that this tribe might have been of Korean origin and had joined the Xiongnu confederation, later returning to Korea and merging with the Silla royal family.

Silla's society, particularly after it became a centralized state, was distinctly aristocratic. The Silla royalty operated a bone rank system, determining one's social status, privileges, and even official positions. Two primary classes of royalty existed: "sacred bone" and "true bone". This bifurcation ended with the reign of Queen Jindeok, the last "sacred bone" ruler, in 654.^[42] While the king or queen was theoretically an absolute monarch, aristocrats held significant influence, with the "Hwabaek" serving as a royal council making crucial decisions, like choosing state religions.^[43] Following the unification, Silla's governance took inspiration from Chinese bureaucratic models. This was a shift from earlier times when the Silla monarchs heavily emphasized Buddhism and portrayed themselves as "Buddha-kings".

Silla's early military structure revolved around royal guards, who protected the royalty and nobility. Due to external threats, especially from Baekje, Goguryeo, and Yamato Japan, Silla developed local garrisons in each district. Over time, these garrisons evolved, leading to the formation of the "sworn banner" units. Hwarang, equivalent to Western knights, emerged as significant military leaders and played pivotal roles in Silla's conquests, particularly the unification of the Korean Peninsula. Silla's military technology, including the Cheonbono crossbows, was renowned for its efficiency and durability. Additionally, the Nine Legions, Silla's central army, consisted of diverse groups from Silla, Goguryeo, Baekje, and Mohe.^[44] Silla's maritime capabilities were also noteworthy, with the navy backing its strong shipbuilding and seamanship.

A significant part of Silla's cultural heritage resides in Gyeongju, with numerous Silla tombs still intact. Silla's cultural artifacts, particularly gold crowns and jewelry, offer insights into the kingdom's artistry and craftsmanship. A key architectural marvel is the Cheomseongdae, the oldest surviving astronomical observatory in East Asia. Internationally, Silla established relations via the Silk Road, with records of Silla found in Persian epic poems like the Kushnameh. Traders and merchants facilitated the flow of cultural and commercial items between Silla and other parts of Asia, particularly Persia.^[45] The Japanese texts, Nihon Shoki and Kojiki, also make references to Silla, recounting legends and historical ties between the two regions.