What happened in 420 ad?
July 10 – The Jin Dynasty ends in China. Liu Yu (Emperor Wu of Liu Song) becomes the first ruler of the Liu Song Dynasty. Nanjing is reinstated as the capital of northern China. The Southern Dynasties begin in China.
Stilicho, with an army of 30,000 men, defeats the Goths north of Verona. Alaric makes a truce, and withdraws eastward to Illyricum. Emperor Honorius and Stilicho are honored with a triumphal march, for the victories against the Goths and Vandals. This becomes the last victory celebrated in Rome.
Demosthenes defeats the Spartan army and Eurylochus is killed during the Battle of Olpae. The Acarnanians and Ambraciots then sign a peace treaty. An Athenian army under Nicias, Hipponicus and Eurymedon defeats a combined Tanagran and Theban army in the Battle of Tanagra.
Angles, Saxons and Jutes invade Britain, marking the beginning of the Old English period (approximate date). Remodelling of the Dome of Baptistry of Neon, Ravenna (Italy) begins (approximate date).
The 4th century was the time period from AD 301 (CCCI) to AD 400 (CD) in accordance with the Julian calendar. The Roman Empire, Gupta India and the Sassanid Persia were the most powerful and hegemonic states.
August 27, 410 C.E., marked an end to the three-day sack of the city of Rome by Visigoths from Eastern Europe. This sack of Rome signaled a major turning point in the fall of the Western Roman Empire.
In 285 AD, Emperor Diocletian decided that the Roman Empire was too big to manage. He divided the Empire into two parts, the Eastern Roman Empire and the Western Roman Empire. Over the next hundred years or so, Rome would be reunited, split into three parts, and split in two again.
in the 1970s when a group of teenagers from San Rafael High School in Marian County would ritualistically smoke marijuana at 4:20 each day. The number 420 became their code for marijuana. The five students called themselves the "Waldos," which referenced the wall they would sit on at their school.
The connection to the Waldos appeared in December 1998. Hager attributed the early spread of the phrase to Grateful Dead followers—after "Waldo" Reddix became a roadie for the Grateful Dead's bassist, Phil Lesh—and called for 4:20 pm to be the socially accepted time of the day to consume cannabis.
According to Time magazine, 420 can be traced to 1971, when a group of five students at San Rafael High School in Marin County, California began meeting at 4:20 p.m. to smoke marijuana. The actual numbers “420” don't have much symbolic significance, Time reported in 2016.
Who was alive in the year 1000?
Ibn al-Haytham (Book of Optics), Avicenna, Averroes, and Abu Rayhan al-Biruni all flourished around the year 1000.
The Year of the Four Emperors, AD 69, was the first civil war of the Roman Empire, during which four emperors ruled in succession: Galba, Otho, Vitellius, and Vespasian. It is considered an important interval, marking the transition from the Julio-Claudians, the first imperial dynasty, to the Flavian dynasty.

Birth of Jesus, as assigned by Dionysius Exiguus in his anno Domini era according to at least one scholar.
Invasions by Barbarian tribes
The most straightforward theory for Western Rome's collapse pins the fall on a string of military losses sustained against outside forces. Rome had tangled with Germanic tribes for centuries, but by the 300s “barbarian” groups like the Goths had encroached beyond the Empire's borders.
AD stands for Anno Domini, Latin for “in the year of the Lord”, while BC stands for “before Christ”.
“Dark Ages” usually refers to the 900 years of European history between the 5th and 14th centuries.
At the time of Jesus, Palestine (the Holy Land) was still part of the Roman Empire, and Roman law and customs were being imposed on the Jewish people. The Jews didn't like the Romans and there was always a great deal of tension between them. The Roman Emperor was called Caesar.
The Han Empire had the longest duration of any empire in a 2,100 year era of imperial rule. It lasted 426 years or about 100 years longer than other long lasting ones such as the Tang and Qing.
In Reality, the Fall of Rome Happened Very Gradually Over Hundreds of Years. Although the dastardly Odoacer is credited with bringing about Rome's downfall, in reality, the history is far more complex and nuanced. Rome wasn't built in a day, and neither was it destroyed by a single incident or individual.
Christians were occasionally persecuted—formally punished—for their beliefs during the first two centuries CE. But the Roman state's official position was generally to ignore Christians unless they clearly challenged imperial authority.
How long did it take for Rome to fall?
Instead, the fall was slow and painful, lasting over a period of two and a half centuries. The ancient city of Rome, according to tradition, was founded in 753 BCE.
Over time, the east thrived, while the west declined. In fact, after the western part of the Roman Empire fell, the eastern half continued to exist as the Byzantine Empire for hundreds of years. Therefore, the "fall of Rome" really refers only to the fall of the western half of the Empire.
710 refers to July 10, just as 420 refers to April 20. This date was chosen for the simple fact that, if you turn the number 710 upside down, you can read the word “oil”, a reference to cannabis concentrates. Just as 420 is the time to light a joint, 710 is the time to dab.
It's 4/20, the day tens of thousands of Americans gather around the country to celebrate a drug that remains illegal in the US: marijuana. April 20 (or 4/20) is cherished by pot smokers around the world as a reason to toke up with friends and massive crowds each year.
Before long, '420' became a common phrase among Grateful Dead followers as code for smoking pot and 4:20 p.m. was thought to be agreed-upon time for such activities. Eventually, the phrase caught on with marijuana-using subcultures around the U.S. and its origin was largely forgotten.
The most credible story traces 4/20 to Marin County, Calif. In 1971, five students at San Rafael High School would meet at 4:20 p.m. by the campus' statue of chemist Louis Pasteur to partake. They chose that specific time because extracurricular activities had usually ended by then.
In 1971, five high school students in Marin County, Calif., created a ritual for getting high. They would meet at 4:20—when most after-school activities were done—and smoke near a specific wall outside of their school, earning them the nickname the “Waldos.” The number became a code for meeting up.
400 BC: After Cyrus has been killed, his Greek mercenaries make their way back to Greece, where Sparta is so impressed with their feats in and march through Persia that they declare war on the Persians. 400 BC: The Carthaginians occupy Malta. 400 BC: The Egyptians successfully revolt against Persian rule.
In 410 C.E., the Visigoths, led by Alaric, breached the walls of Rome and sacked the capital of the Roman Empire. The Visigoths looted, burned, and pillaged their way through the city, leaving a wake of destruction wherever they went.
In the fourth century AD, however, what Pliny the Elder had called the 'immense majesty of the Roman peace' was menaced by invasions of Germanic peoples from beyond the frontiers of the Rhine and the Danube. Among them were the Visigoths, whose leader from around 395 was a chieftain in his mid-20s named Alaric.
What was the period of 400 800 AD called Why was it significant?
In much of northern Europe, the first four centuries a.d. are referred to as the Roman Iron Age, while the period c. a.d. 400–800 is often termed the Late or Germanic Iron Age.
Roman Empire
A riot breaks out in Constantinople; the Great Palace is burned to the ground. Gainas, a Gothic leader, attempts to evacuate his soldiers out of the city, but 7,000 armed Goths are trapped and killed by order of Arcadius.
Year 400 BC was a year of the pre-Julian Roman calendar. In the Roman Republic, it was known as the Year of the Tribunate of Esquilinus, Capitolinus, Vulso, Medullinus, Saccus and Vulscus (or, less frequently, year 354 Ab urbe condita).
400 BC in history means four hundred years
Internal conflict and ongoing pressure on the borders of the Roman empire lead to the incorporation of barbarian leaders and their followers into the Roman army. ca. 400 A.D. Mass migrations of Germanic tribes north of the Roman empire disrupt the rhythm of life in the provinces and create widespread disorder.
Due to ingenious tactics carried out ruthlessly, the Mongols conquered more land in 25 years than the Romans did in 400. At the height of its powers the Mongolian Empire stretched over 9.27 million squaremiles.
When it comes to the personal lives of female slaves, they were not allowed to marry fellow slaves, or to keep their children. Even though formal marriage, conubium, was forbidden, illegal unions like marriages were common.
Invasions by Barbarian tribes
The Romans weathered a Germanic uprising in the late fourth century, but in 410 the Visigoth King Alaric successfully sacked the city of Rome. The Empire spent the next several decades under constant threat before “the Eternal City” was raided again in 455, this time by the Vandals.
Corruption, the division of the empire, and invasion by Germanic tribes were the three main causes of the fall of Rome. Some scholars believe that there were other contributing factors as well.
The fall of Constantinople to the Ottoman Empire, in 1453 CE, marks the end of the dark ages. The Middle Ages time period took place from 500 CE to 1500 CE in Europe. This was a time in history that fell between the end of the Roman Empire and the modern format of European lands.
How many Dark Ages have there been?
So, in Western Europe, two 'dark ages' can be identified, separated by the brilliant but brief Carolingian Renaissance.
The idea of the “Dark Ages” came from later scholars who were heavily biased toward ancient Rome. In the years following 476 A.D., various Germanic peoples conquered the former Roman Empire in the West (including Europe and North Africa), shoving aside ancient Roman traditions in favor of their own.