Stiftskeller St. Peter, a restaurant within the monastery walls of St. Peter's Archabbey, Salzburg, Austria, is claimed to be the oldest inn in Central Europe because of a document mentioning it in 803.

Stiftskeller St. Peter is believed to be one of the oldest continuously operating restaurants in the world, and the oldest in Europe.

Nikephoros’s rule is endangered by Bardanes Tourkos, one of his ablest generals, who revolts and receives support from other commanders, notably the later emperors Leo V the Armenian and Michael II the Amorian in 803.

Nikephoros gains over the latter two, however, and by inducing the rebel army to disperse achieves the submission of Bardanes, who is relegated to a monastery and blinded there.

A conspiracy headed by the patrician Arsaber has a similar result.

The deposition of Empress Irene and subsequent accession of Nikephoros I signals a more violent phase in the long history of the Arab–Byzantine Wars.

Following a series of destructive annual raids across Asia Minor by the Caliphate, Irene seems to have secured a truce with Harun al-Rashid in 798 in exchange for the annual payment of tribute, repeating the terms agreed for a three-year truce following Harun's first large-scale campaign in 782.

Nikephoros, on the other hand, is more warlike and determined to refill the imperial treasury by, among other measures, ceasing the tribute.

Harun retaliates at once, launching a raid under his son al-Qasim.

Nikephoros cannot respond to this facing the ultimately unsuccessful revolt of the Asian army under Bardanes Tourkos.

After disposing of Bardanes, Nikephoros assembles his army and marches out himself to meet a second, larger invasion under the Caliph himself.

After Harun raids the frontier region, the two armies confront each other for two months in central Asia Minor, but it does not come to a battle; Nikephoros and Harun exchange etter until the Emperor arranges for a withdrawal and a truce for the remainder of the year in exchange for a one-off payment of tribute.

Nikephoros embarks on a general reorganization of the Empire, creating new themes in the Balkans and strengthening the frontiers.

Needing large sums to increase his military forces, he sets himself with great energy to increase the Empire's revenue, reimposing the taxes that Irene had remitted, and instituting other reforms that provide some insight into the financial administration of the empire during the early ninth century.

By his rigorous tax imposts he alienates the favor of his subjects, and especially of the clergy, whom he otherwise seeks to control firmly.

Although he appoints an iconodule, Nikephoros, as patriarch, Emperor Nikephoros is portrayed as a villain by ecclesiastical historians like Theophanes the Confessor.

He crowns his son Staurakios co-emperor in December 803.

In the same year, Nikephoros concludes a treaty, called the "Pax Nicephori", with Charles I of the Franks, but refuses to recognize the latter's imperial dignity.

Nikephoros, in the tradition of Constantine V, strengthens the fortifications of Thrace by settling in this theme Greek colonists from Asia Minor.

Nikephoros I, on becoming emperor after Irene was deposed, had refused to pay tribute to Harun, saying that Irene should have been receiving the tribute the whole time.

News of this angers Harun, who writes a message on the back of the Roman emperor's letter and says,

"In the name of God the most merciful, From Amir al-Mu'minin Harun al-Rashid, commander of the faithful, to Nikephoros, dog of the Romans.

Thou shalt not hear, thou shalt behold my reply".

Harun’s capital at Baghdad, renowned for the magnificence of his court, has become a vigorous center of commercial activity.

The administration of the 'Abbasid empire has for more than sixteen years been mainly the responsibility of members of the priestly Barmakid family, who have provided the money for the luxury and extravagance of Harun al Rashid's court.

Ja'far ibn Yahya, who had inherited the position of vizier to the caliph from his father, Yahya, has a reputation as a patron of the sciences, and has done much to introduce Greek science into Baghdad, attracting scholars from the nearby Academy of Gundishapur to help translate Persian works into Arabic (the so-called "Translation Movement").

He is also credited with persuading the caliph to open a paper mill in Baghdad, the secret of papermaking having been obtained in 751 from Chinese prisoners at the Battle of Talas in present day Kyrgyzstan.

Moreover, Ja'far has become Harun's special friend, so that gossip speaks of a homosexual relationship.

Gossip also alleges that Harun had arranged that Ja'far should secretly marry his sister 'Abbasah, on condition that he did not consummate the marriage, but Ja'far fell in love with her, and she had a child.

Whether in anger at this or not, Harun has the thirty-six-year-old Ja'far executed on January 29, 803, and parts of his body displayed on the bridges of Baghdad.

The other members of the family are imprisoned and their goods confiscated.

Diverse interests within the 'Abbasid empire are being attracted to two opposing poles.

On the one side are the “secretaries’”, or civil servants, many Persians, and many men from the eastern provinces; on the other side are the religious scholars ('ulama'), many Arabs, and many from the western provinces.

Since the Barmakids favor the first group of interests and the new vizier, al-Fadl ibn ar-Rabi', favors the second, it is likely that this political cleavage is involved in the change of ministry.

The deposed empress Irene, exiled to Lesbos, has been forced to support herself by spinning.

She dies on August 9, 803, at fifty-one.

Her zeal in restoring icons and her patronage of monasteries will, however, ensure her a place among the saints of the Greek Orthodox Church.

The son of Idris I, born a few months after his father's assassination and called Idris also, is proclaimed imam of the Awr'ba in 803, when he is still a young boy.

His mother Kenza, the wife of Idris I, is the daughter of the chief of the Berber Awarba tribe.

Idris II, having never met his father, has been raised among the Berbers of Volubilis.

Pope Leo helps restore King Eardwulf of Northumbria and settles various matters of dispute between the Archbishops of York and Canterbury.

He also reverses the decision of his predecessor Pope Adrian I, in regards to the granting of the pallium to Higbert, Bishop of Lichfield.

He believes that the English episcopate had been misrepresented before Adrian and that therefore his act was invalid.

Lichfield is in 803 a regular diocese again.

The Nanzhao Tai state of South China temporarily vassalizes the Pyu center of Srikshetra in the early 800s.

Denmark is apparently united by around 800, primarily in opposition to northward expansion by the Franks under Charles I.

Contemporary Frankish annals begin in 804 to record individual kings of the Danes with whom Charles wars as his Carolingian Empire absorbs the peoples and territories to the immediate south of the Danevirke.