In the 1220s and 1230s, Mongol hordes appeared on the scene. Having conquered the northeastern part of China (1211-1215), the Mongol leader Genghis-Khan marched out against Central Asia, launching an offensive on Muhammad, Shah of Khwarizmi (1200-1220). The detachment of the Mongol army, led by Djebb and Subudai, the same detachment, that had made war on Muhammad and his son Jalal-ad-Din (1200-1231), attacked Georgia several times in the early 1220s. Jalal-ad-Din took Tbilisi. By 1240 the entire country was under the Mongol yoke. The Mongols contented themselves with putting the King to death. Demetre II was canonized and is known in history as Demetre the Self-Sacrificer. In the first half of the 14^th century Giorgi V the Brilliant (1314-1346) pursued a wise, flexible policy, aimed at overthrowing the Mongol yoke and restoration of Georgia's unity. In 1329, the King incorporated Western Georgia, and in 1334 the principality of Samtskhe. Thus, Georgia actually freed herself from Mongol ruling.

Having been liberated from the Mongol oppression, the country began to revive, but this period was destined to be short-lived.  The cruelest conqueror to have ever invaded Georgia was Tamerlane, who conquered the whole India within 14 months, but spent more than 15 years trying to subdue Georgia! During 1386-1403, he attacked Georgia 8 times and left terrible devastation behind.

The inroads of the Ottoman Turks - no less devastating than Tamerlane’s invasion -began in the first decade of the 15^th century. In 1453 the Ottoman Turks finally destroyed the Byzantine Empire and in 1461 the Kingdom of Trebizond. In 147, the Khanate of the Crimea became a vassal of Turkey and threatened Georgia from the north-west as well. Georgia was now practically cut off from new international trade routes and deprived of the chance to establish direct contacts with European countries. This worsened the economic and cultural decline of the country; commerce and handicrafts fell into decay, and some cities ceased to function from the constant invasions. The royal power weakened, and the isolationist tendencies of individual feudal lords became apparent.

The process of the decline and disintegration of the single Kingdom began in the 13^th-14^th and deepened in the 15^th century. At the turn of the 15^th and 16^th centuries, the Kingdom broke up into separate political units, viz. into the Kingdoms of Kartli (Iberia), Kakheti and Imereti, and the principality of Samtskhe. Several principalities fell away from the Imeretian Kingdom: Odishi, Svaneti, Guria and Abkhazia. Divided into several administrative units, Georgia was torn by feuds.

In the 16^th century, Iran and Turkey contended for supremacy in the Near East. Georgia turned into one of the arenas of hostilities between them. In 1513 David V (1505-1525), King of Kartli (Iberia), incorporated the Kingdom of Kakheti, but failed to preserve this unity. In 1522 Ismail I, Shah of Iran, attacked Kartli. Taking and sacking Tbilisi, he stationed his garrison in its citadel. Then he took Samtskhe-Saatabago, returning to Iran loaded with captives and plunder. In 1524, the Georgians liberated Tbilisi. In the same period, Western Georgia became the target of Turkish aggression. According to the Treaty of Amasya, signed by Iran and Turkey, Western Georgia fell to Turkey, while Eastern Georgia and the eastern part of Samtskhe-Saatabago to lran. After the conclusion of this treaty, the Georgians' struggle for independence continued under conditions that were more difficult. The Kartli (Iberia)an Kingdom never surrendered. In 1556, the Georgians, led by King Simon I (1556-1568 and 1578-1600), routed the Iranian army. Submitting to Iran, Kakheti succeeded in preserving peace.

At the beginning of the 17^th century Abbas I, Shah of Iran, drove the Turks out of Armenia, Kartli and Kakheti. The Turkish yoke was superseded by that of Iran. But in 1609 Kartli was invaded by the Turks and Crimean Tatars. In 1614, Shah Abbas I attacked Kakheti. Then, invading Kartli he stationed his garrisons in all the fortresses. In 1615, Kakheti rose against the Persians; the fortresses were cleared of the enemy. In 1616, Abbas I again invaded Kakheti and Kartli, razing many fortresses, churches, monasteries and palaces; orchards and vineyards were cut down. A great many Georgians perished. One hundred thousand were taken prisoners, their descendants lice in the province of Fereidan in Iran to the present day.

Finding herself encircled by aggressive states and with a view to preserving her statehood, Georgia appealed to Russia for help. With the help of Russian King, Vakhtang Vl (1703-1724) tried to throw off Iranian domination. Back in 1720, the Emperor Peter I of Russia had begun diplomatic negotiations with the people of Transcaucasia. The Emperor urged the King of Kartli to come over to his side, promising to rid him of the oppression of the "infidels". Such bilateral interests led to a military and political relationship between Kartli and Russia. In June 1722 ,Peter I issued a manifesto on a military campaign against Iran. According to this plan, the Georgian and Armenian armies arrived at Ganja but they were not to meet the Russian army: Owing to difficulties in Russia’s foreign and home affairs, Russia canceled the campaign. In retaliation, the Shah dethroned Vakhtang Vl and gave Kartli to Constantine, the ruler of Kakheti. The latter laid siege to Tbilisi with an army of Daghestanian mercenaries (1723). The capital was taken and sacked. Vakhtang established himself in Shida (Inner) Kartli (Iberia), while Constantine occupied Tbilisi. In the same year Tbilisi was seized by a Turkish army.

In 1724, according to a treaty signed by Russia and Turkey, the latter recognized the western and southern coasts of the Caspian Sea as the property of Russia. In return, Peter I ceded Eastern Georgia, Armenia, Azerbaijan and Northern Iran to the Turks. The plan of liberating Georgia actually failed. With the consent of Peter I Vakhtang Vl, accompanied by his family, his brother, his close comrades-in-arms and a large retinue, left for Russia on June 15, 1724.