In 1570, the Crimean Khanate had devastated terribly the Ryazan borderland of Muscovy, not meeting strong resistance.
In May 1571, the 120-thousand Crimean and Turkish army (80,000 Tatar, 33,000 irregular Turks and 7000 janissary) led by the khan of Crimea Devlet I Giray, and Big and Small Nogai hordes and troops of Circassians, bypassed the Serpukhov defensive fortifications on the river Oka, crosses the river Ugra and rounds the flank of the 6000 man Russian army.
The sentry troops of Russians are crushed by the Crimeans.
Not having forces to stop the invasion, the Russian army recedes to Moscow.
The rural Russian population also flees to the capital.
