Vasily has to flee the capital in 1439, when it is besieged by the Khanate of Kazan.

The Golden Horde has begun fragmenting into a number of khanates, including that of…

…Kazan', formed in 1438 under Ulugh Muhammad, and …

…the Crimea Khanate.

The Khanate of the Crimea originates in the early fourteenth century when certain Turkish clans of the Golden Horde Empire cease their nomadic life in the Desht-i Kipchak (Kypchak Steppes of today's Ukraine and southern Russia) and decide to make Crimea their yurt (homeland).

At this time, the Golden Horde of Mongol empire had governed the Crimean peninsula as an ulus since 1239, with its capital at Qirim (Staryi Krym).

The local separatists had invite a Genghisid contender for the Golden Horde throne, Hacı Giray, to become their khan.

Accepting their invitation, Hacı Giray had traveled from exile in Lithuania and has warred for independence against the Horde from 1420 to 1441, in the end achieving success.

The Crimean Tatars, led by Haci Giray, establish a khanate at Bakhchysarai in 1446.

Haci Giray had ascended the throne after a long struggle against the khans of the Golden Horde for the independence of the Crimean Khanate in which he was supported by the Grand Duchy of Lithuania.

While some sources state he came to power as early as 1428 or 1434, the first coins of Haci Giray are not earlier than 1441.

The founder the Giray Dynasty of the Crimean Khans, Haci Giray introduces the new state symbol: "taraq tamğa" or "the trident of Girays", which is a derivation from the scales insignia of Golden Horde.

He establishes his residence in Salaçıq village (the vicinities of modern Bakhchisaray near the Çufut Qale fortress).

A contemporary European source, The Chronicle of Dlugosz, described him as a person of outstanding personal values and a perfect governor.

The causes of the Muscovite Civil War waged in the second quarter of the fifteenth century are still disputed.

However, Dmitri Donskoi's will ran contrary to Rurikid dynastic custom, whereby the throne would pass from an elder brother to a younger one (lateral inheritance), rather than from father to son (linear succession).

The testament had provided for the accession of his son, Vasily I, which was still in keeping with the tradition of lateral succession, since Vasily was the eldest of his generation.

In the event of Vasily having no surviving son at his death, his brother, Dmitry's second son, Yury of Zvenigorod, was to succeed as grand prince in Moscow.

Upon Vasily I's death, however, Yury had refused to come to Moscow and swear allegiance to his nephew, Vasily II, and claimed the throne himself in accordance with his right under the long-held custom of lateral inheritance.

(He further claimed it was provided for in Dmitry's testament—but this ignored the provision that voided Yury's succession in the event of Vasily I producing a son).

Yury's son, Dmitry Shemyaka, had actively participated in all of his father's incursions against Moscow, culminating in Yury's capture of Moscow and accession as grand prince in 1433.

Yury of Zvenigorod had died in Moscow in 1434.

After Yury's death, Shemyaka continued to press his branch's claim to the grand princely throne, and was seldom at peace with Vasily II.

Initially, Dmitry and his younger brother Dmitry Krasnyi had concluded an alliance with Vasily against their elder brother Vasily Kosoy, who had proclaimed himself grand prince.

They had succeeded in driving Kosoy from Moscow and were rewarded with the towns of Uglich and Rzhev.

The following year, Shemyaka had come to Moscow in order to invite Vasily II to his impending wedding with a princess of Yaroslavl, but was accused of siding with Kosoy and taken prisoner.

Released several months later, he was sent by Vasily II to defend Belyov against a small army of the Kazan Khan Olugh Mokhammad but had been defeated.

Thereupon he refused to support Vasily in his hostilities against the khan, and only the mediation of a hegumen from the Trinity Lavra of St. Sergius monastery forestalled a new civil war between the cousins.

The two men had maintained an uneasy peace for much of the next decade until 1445, when Vasily II is taken prisoner by Olugh Mokhammad after the Muscovite forces are surprised by the Tatar prince outside Suzdal.

The Tatar khan also expropriates boyar estates.

Shemyaka seizes Moscow, has the recently released Vasily blinded and proclaims himself the Grand Prince of Vladimir.

He can claim this by right of lateral inheritance since, his father had sat on the throne.

(A prince is excluded from the succession (izgoi) if his father had not sat on the throne before him.)

Shemyaka's lack of support among the Muscovite boyars forces him, however, to leave the city for Lake Chukhloma, but he continues to press his claim to the grand princely throne.