A Sarmatian timeline

Below is a general timeline of Sarmatian activities. Much of it is taken from the New Penguin atlases, and sometimes the only information given is their spot on the map. Other times, they're discussed in more detail in the text. I've supplemented in a few additional notes from elsewhere and will continue to update this post as needed.

Note that overall, there is a general trend among western steppe nomads to eventually be pushed westward by tribes moving in from the east.

• By 415 BC, the Sarmatians are inhabiting the Russian steppes north of the Caspian Sea.
• By 192 BC, the Sarmatians are pushing the Scythians westward.
• By 145 BC, Sarmatians can be divided into three sub-groups (Jazyges, Roxolani, and Alan), each group's area is delineated east-west by major rivers. 
• By 79 AD, the Sarmatians are being pushed westward to the point that the Roxolani cause the Jazyges to be displaced to the Hungarian steppes.
• By 230, the Jazyges have been further restricted by Vandals moving in from the north, while the Roxolani are actually pushed back toward the Alans by the Goths moving in from the west.
• By 305, the Roxolani and Jazyges are no longer on the map. Their areas have been taken over by Asding Vandals and Ostrogoths.
• By 362, the Alans are feeling the heat from three sides- the Ostrogothic Empire to the West, the Finns to the north, and the Huns to the east. They live in a small area between the Black and Caspian seas north of the Caucasus Mountains. They then expand south into  the mountains.
• Throughout all this, approximately 250,000 people live on the steppes between those two seas at a given time.
• By 406, the Huns have taken over the steppes, pushing Germanic tribes west- along with a clan of Alans. The Vandals, Suevi, and the Alan clan invade Gaul at the end of the year.
• By 420, the aforementioned barbarian pillagers have moved into the Iberian peninsula. As part of a bargain with Rome, the Visigoths pushed most of them into the northwest corner before returning to Gaul.
• In 429, the Asding Vandals leave their corner of the Iberian peninsula, pick up the Siling Vandals and Alans left in the south, and 80,000 men, women, and children cross the Straight of Gibraltar into Africa. Rome has to cede the western provinces (the northernmost parts of modern Morocco and Algeria) to them in 435. In 442, they trade them for modern Tunisia. The Alan king had died in battle before this and the clan was absorbed by the Vandals they traveled with.
• By 476, the Alans who stayed behind during the Huns' rule have regained ground in and around the east Caucasus.
• By 600, the Khazar Turks have pushed the Alans out of their northern reaches. The Alans are able to push the Huns back slightly to the west.
• By 661, the Khazars have expanded and now rule the Alans.
• By 1030, the Alans are back on the map in the east Caucasus. (It's a long stretch of time, but stuff happened in between which was not intimated in the book.)
• By 1071, the Alans now hold almost all of the steppes between the Black and Caspian seas and north of the Caucasus. The Kingdom of Georgia is to their southwest.
• By 1092, the Alans have lost some of their northern lands and gained some in the eastern Caucasus.
• From 1221-1222, a group of Mongols originally sent to pursuethe Shah out of his empire to the south fights their way through several groups' lands, including the Alans, and deep into Russia. The Mongol attacks are damaging, but Genghis Khan dies before he can take advantage of them.
• In 1236, the Mongols return to the Russian steppes. No one has bolstered their defenses and the Alans fall under Mongol subjugation along with other groups. 

That is the last they are mentioned in the New Penguin books, but the Encyclopaedia Iranica gives more information on their eventual fate from other references. After devastating wars in the 14th centuries, the Alans split into three groups- one moved into the foothills of the central Caucasus and became the Iron and Digor Ossetians still around today. Another migrated to Hungary and became the Jasz (It seems I was wrong before about them being descended from the Jazyges. Though I'm still puzzled by the name parallel.) The third took up with the Mongols and were sent to China as guards (the Mongols and Chinese called them "Asu" or "As"), where they were eventually absorbed or killed in battle.

McEvedy, C., 2002, The New Penguin Atlas of Ancient History, 2nd ed., Penguin Books.
McEvedy, C., 1992, The New Penguin Atlas of Medieval History, Penguin Books.
Yule, H., 1913, Cathay and the way thither: being a collection of medieval notices of China, Vol. III, Hakluyt Society, London.
The History of Yuan (pīnyīn: Yuán Shǐ), 1370, ed. Song Lian, Ming Dynasty Bureau of History, China.