Li Kuo briefly serves as regent when Emperor Daizong falls ill in 779, and when Emperor Daizong subsequently dies, succeeds him as Emperor Dezong.

The Samye monastery, the first Buddhist monastery built in Tibet, is most probably first constructed between 775 and 779 CE under the patronage of King Trisong Detsen of Tibet who seeks to revitalize Buddhism, which had declined since its introduction by King Songtsen Gampo in the seventh century.

The monastery, located in present Dranang, Shannan Prefecture, and supposedly modeled on the design of Odantapuri monastery in what is now Bihar, India, features an architectural mandala (Sanskrit for "circle"), a symbolic diagram of the universe, used in Tantric Buddhism for ritual purposes.

The conflict initiated by Charlemagne between the Franks and Spain’s Muslims and Christian Basques continues as a series of skirmishes with the people of Aquitaine.

Charles again goes into Saxony in summer 779 and conquers three of its four divisions: Eastphalia, Engria, and Westphalia.

At a diet near Lippspringe, he divides the land into missionary districts and Frankish countships.

With Saxony now at peace in 780, Charles himself assists in several mass baptisms before returning to Italy.

Cynewulf is defeated by Offa of Mercia at the Battle of Bensington in 779; Offa then retakes Berkshire, and perhaps also London.

Despite this defeat, there is no evidence to suggest Cynewulf subsequently became subject to Offa (as his successor, Beorhtric, did).

Lu Yu was born in 733 in Tianmen, Hubei.

According to Tea Lore, Lu Yu was an orphan of Jinling county (now Tianmen county in Hubei province) who was adopted by a Buddhist monk of the Dragon Cloud Monastery.

He refused to take up the monastic robes and was assigned menial jobs by his stepfather.

Lu Yu ran away and joined the circus as a clown.

At age fourteen, Lu Yu was discovered by the local governor Li Qiwu who offered Lu Yu the use of his library and the opportunity to study with a teacher.

For six years, Lu Yu stayed in Houmen mountain studying under the guidance of master Zou Fuzi.

During this period Lu Yu often brewed tea for his teacher.

He also took care of fellow students' health with his remarkable knowledge in tea and herbs that he learned while at the Longgai Monastery.

Whenever time permitted between his studies Lu Yu often went to the countryside to gather tea leaves and herbs.

In one of those trips Lu Yu stumbled upon a spring underneath a six-foot round rock and the water from the spring was extremely clear and clean.

When Lu Yu brewed tea with this spring water he found the tea tasted unexpectedly better than usual: Lu Yu now realized the importance of quality water in brewing tea.

Zou Fuzi, moved by Lu Yu's obsession with tea and his skill in brewing good tea, cleared the rock together with some of his students and dug a well around the fountainhead of that spring.

(In 1768, just over a thousand years later during the Qing Dynasty (1616–1911), Jingling was hit by drought and the whole city was badly in need of water.

City folks found water still flowing from this well uncovered by Lu Yu and dug by Zou Fuzi.

A Qing official ordered three wells to be dug around the spring, and a structure constructed near the wells named "Lu Yu Hut" and the "Literary Spring".)

Concluding his studies in 752, Lu Yu bade farewell to his guru Zou Fuzi and returned to Jingling to meet his benefactor Li Qiwu.

However, Li Qiwu had been reinstated the previous year and had returned to the Tang capital Chang'an; the new Chief Official of Jingling now was Cui Goufu.

Cui, a senior official who had held a position approximating an Education Minister, had been demoted and transferred to Jingling as a Chief Official for offending a member of the royalty.

Cui Goufu is a scholar and poet well known for his magnificent five-characters-per-verse short poems.

After his demotion to Jingling, Cui Goufu took life at his leisure.

Even though Cui was many years older than Lu Yu, both men share the same interest in tea, literature and poetry.

As such, they had become good friends soon after they met.

During this period, Lu Yu had stayed with Cui Goufu and assisted him in his administrative tasks.

The pair had spent much time traveling, drinking tea and writing poems, co-authoring several books on poetry.

This period with Cui Goufu had been the growing phase for Lu Yu as a man of letters; an incubation period for him to practice and sharpen what he had learned from Zou Fuzi.

Cui Goufu, with his vast experience and skill in literary work, became a coach who provided the necessary guidance to enhance and mature Lu Yu's writing and literary skills.

During this time he writes Cha Jing (The Classic of Tea), publishing it between 760 and 780 as three books covering ten chapters.

According to Cha Jing, tea drinking is widespread.

The book describes how tea plants are grown, the leaves processed, and tea prepared as a beverage.

It also describes how tea is evaluated, and discusses where the best tea leaves are produced.

Charles, having suppressed a revolt in Lombardy in 776, reinvades again in 780 to strengthen the papacy and install his son as king.

Leo at the beginning of his reign had not attempted to continue the fierce iconoclastic policy pursued by his father and grandfather, forbidding the use of icons.

Instead, he has shown considerable moderation toward the proponents of icons, even appointing them to bishoprics.

This action may have resulted from the influence of the strongly orthodox Irene.

In 780, however, he reverses his policy and initiates a persecution of those favoring the use of icons.

He dies prematurely, at thirty-one, on September 8, 780, leaving to succeed him his nine-year-old son, Constantine VI, under the regency of the empress Irene.

Later in this year, Irene crushes what seems to have been a plot by the Iconoclasts to put Leo's half brother, Nikephoros, on the throne.

Caliph al-Mahdi, in retaliation for the Romans' post-battle slaughter of his army in 778, has assembled a large force of Mesopotamians, Syrians, and Khorasanians, which he leads northwards in late 780 Aafter the death of Emperor Leo IV, who had campaigned against the Arabs in Anatolia and Syria since 777.

Empress Irene, acting regent for her young son Constantine VI, orders the imperial forces to annihilate the invading Muslims.