So we know about 690 AD being the year of the ascension of Empress Wu Zetian to the throne of China, and that much of the action of the Ancient Juncture focuses on goings-on in and around China in general. But what else would be going on around the world at around that time period?
Well for starters, while the Western Roman Empire may have fallen since the 69 AD era, the Eastern Roman Empire, a.k.a. the Byzantine Empire, is still going strong in 690 AD. It is currently ruled by Emperor Justinian II, the last of the Heraclian Dynasty of Byzantine emperors and an all-around ruthless son of a bitch. Like the first Emperor Justinian, Justinian II wants to restore the glory of the old Roman Empire, but lacks the finesse of his father Constantine IV and often brutally suppresses opposition to his will. He is currently engaged in a war with the Arabs after his successful expedition against the Slavs of Macedonia, but his brutal taxation policies to support this war are anything but popular with his people, and will eventually drive them to rebellion against him, leading to his overthrow and exile with the help of the aristocracy in 695 along with the cutting off of his nose.
Meanwhile:
- The Mayan Empire in Central America is at its height, and temples are being built in order to harness the chi of the region, among them the Temple of the Sun.
- England is divided into four major kingdoms, Kent, Mercia, Northumberland and Wessex, that will soon be united in a few centuries under the Anglo-Saxon kingdom of Wessex before being conquered by the Normans in 1066.
- Elsewhere, France, or as it was known back then, Francia, is ruled by the Franks, and is among the largest of the post-Roman barbarian kingdoms of Europe; its capital has changed a number of times, but right now, it is in Paris, which will in time become the capital of modern France. It is still rather divided, but true unification won't come until the rule of Charlemagne in 768.
- In the meantime, Spain, or as it was known back then, Hispania, is part of the Visigothic Kingdom, one of the Germanic successor states to the Western Roman Empire.
- In Africa, Egypt is ruled by the Umayyad Caliphate after having been conquered and converted to the fairly recently established faith of Islam, and is ruled from its new capital of Cairo. Unfortunately, the caliphate is in the midst of a civil war over control over the ruling dynasty that will result in tribal rifts and the foundation of what will become the Sunni and Shi'a denominations of Islam.
- Japan is in the Asuka Period, where much of the really formative aspects of Japanese culture, including Buddhism and Taoism, are taking shape, and is ruled by Empress Jito.
- Korea is in the middle of the Unified Silla era, where the Korean kingdom of Silla unified central and southern Korea by conquering Baekje and Goguryeo. It is currently ruled by King Sinmun, the son of King Munmu, the guy who unified Silla.
- Much of India is ruled by the Chalukya dynasty under King Vinayaditya, and much war is going on between the Chalukyas and a number of the other kingdoms of India and Southern Asia.
And there's some other stuff going on too that I'm not really up on considering that ancient history tends to not be too well known outside of Wikipedia and elsewhere.