The Lombards, one of the Germanic tribes that formed the Suebi, had by the end of the fifth century moved from their home in northwestern Germany into the area roughly coinciding with modern Austria north of the Danube River.

Their ruler for the past three decades has been Wacho, who had assassinated his uncle Tato and usurped the throne about 510.

Tato's son and grandson had taken refuge with the king of a neighboring Germanic people, the Gepidae, making several fruitless attempts to recover rule over the Lombards.

Shortly after 536, Waccho had made a treaty with Justinian against the Gepids.

Vitiges, King of the Ostrogoths in Italy, hard-pressed by Justinian's general Belisarius, sends ambassadors to Wacho in 539, offering him money in exchange for military aid.

Wacho refuses, preferring to remain on good terms with Constantinople.

Having also good relations with the Franks, Wacho has married off his daughter, Waldrada, to the Frankish prince Theudebald, son of Theudebert of Metz.

Their granddaughter is Theodelinda, who will later become queen of the Lombards.

He his second marriage was to a Gepid princess, Austrigusa, called "Ostrogotha" (perhaps due to her maternal descent from Ostrogothic rulers).

Austrigusa was the mother of two daughters: Wisigarda (who married Theudebert I of Austrasia) and Waldrada (who married firstly Theudebald of Austrasia, secondly Chlothar I, King of the Franks, and thirdly Garibald I of Bavaria).

Wacho's third marriage was to Silinga, a Heruli, and the mother of his son Walhtari.

At the death of Wacho in 539, Walthari rules as an infant king, and his government is administered by Audoin as regent.

Justinian becomes alarmed by renewed barbarian incursions across the Danube frontier from the Slavs, the Bulgars, the Gepids, and the Avars.

The Arab Christian Ghassanids of southern Syria are Roman allies, forming a buffer zone against the other Bedouins penetrating Roman territory.

Their capital is Jabiyah in the Golan Heights.

Geographically, the Ghassanid kingdom occupies much of Syria, Mount Hermon (Lebanon), and Palestine, and its authority extends via tribal alliances with other Azdi tribes all the way to the northern Hijaz as far south as Yathrib (Medina).

Al-Harith ibn Jabalah, king of the Ghassanids from 529, has continued to support the Roman Empire against Sassanid Persia and had been given the title patricius in 529 by Justinian.

He is an adherent of Miaphysitism, the doctrine that in the one person of Jesus Christ, Divinity and Humanity are united in one "nature" ("physis"), the two being united without separation, without confusion, and without alteration.

The term "miaphysitism" had arisen as a response to Nestorianism.

As Nestorianism had its roots in the Antiochene tradition and was opposed by the Alexandrian tradition, Christians in Syria and Egypt who wanted to distance themselves from the extremes of Nestorianism and wished to uphold the integrity of their theological position adopted this term to express their position.

The Council of Chalcedon had in 451 condemned Monophysitism, of which they had considered Miaphysitism to be a form, but the Oriental Orthodox Churches reject this characterization.

Al-Harith supports opponents of the Council and in the region, where he has helped to revive the Syriac Orthodox Church despite the disapproval of Orthodox Constantinople.

Germanus has spent the past two years in reestablishing discipline in the army.

Finally, Justinian judges the situation to have been stabilized enough, and in 539 Germanus is replaced by Solomon, who carries on Germanus' work by pruning out of the army those of suspect loyalties and strengthening the network of fortifications.

This careful organization enables him to strike successfully against the Aurasii, evicting them from their mountain strongholds, and firmly establish Roman rule in Numidia and Mauretania Sitifensis.

The Alemanni, following their defeat in 496, had bucked the Frankish yoke and put themselves under the protection of Theodoric the Great of the Ostrogoths, but they are in 539 again subjugated by the Franks under Theudebert I.

Alamannia becomes a nominal dukedom within Francia.

The Goths and their Burgundian allies recapture Mediolanum (modern Milan) in March, after many months of siege, the city having reaching the point of starvation.

The imperial garrison (one thousand men) surrenders and is spared, but the inhabitants are massacred (according to Procopius three hundred thousand people are murdered) and the city itself is destroyed.

The Ostrogoths lose control of Trieste to the imperial forces in 539.

Belisarius, still besieging Ravenna, the last major stronghold in the north, negotiates a treaty with Theudebert I (whose forces are suffering from dysentery) and the Franks retreat to Gaul.

The Imperial fleet controls the Adriatic Sea and blockades the port of the capital from supplies.

Vitiges surrenders in late 539.

The global environmental cooling seen in the year 540 is probably due to a comet impact, evidenced by global tree ring growth diminution.

(Baillie, M.G.L.

(2007).

Tree-Rings Indicate Global Environmental Downturns that could have been Caused by Comet Debris, Chap.

5 in Bobrowsky, Peter T. and Hans Rickman (eds.

), Comet/Asteroid Impacts and Human Society: An Interdisciplinary Approach, Springer-Verlag, Berlin.

ISBN 3-540-32709-6, pp.

105–122.)

Khosrau has built defensive walls on the frontier against the Romans and their Arab allies in the Syrian Desert, against the peoples of the steppes of southern Russia at the town of Derbent between the Caucasus Mountains and the Caspian Sea, and to the east of the sea in the present Turkmen steppes.

The army does not remain on the defensive, however: Khosrau's reign is noted for his wars against the Romans.

Jealous of Justinian's victories in the West, Khosrau receives an embassy from the Ostrogoths at Ctesiphon, urging him to act before the Romans become too powerful.

Fearing Constantinople’s growing strength and intolerance of Zoroastrianism, he invades Syria in 540, breaking the “eternal” peace concluded eight years earlier.