Francis of Assisi, to whom Pelagio reluctantly…

Genghis Khan launches his campaign against the Khwarezmian dynasty in 1219, and requests military aid from their allies and tributaries.

However, despite having aided the Mongols against the Jin dynasty, the Western Xia emperor and his military commander Aša-gambu refuse to take part in the campaign, stating that if Genghis has too few troops to attack Khwarezm, then he has no claim to supreme power.

Infuriated, Genghis swears vengeance and leaves to invade Khwarazm, while Western Xia attempts alliances with the Jin and Song dynasties against the Mongols.

Genghis Khan, receiving no reparations from the Khwarezem Shah, declares war on Persia, consisting at this time of Khwarezm, Transoxiania, and Khorasan.

The Mongol troops approach the walls of Otrar in autumn 1219.

Shortly before, the Mongols had appeared in Kunya Urgench, the capital of the Khwarezmian Empire, where a war council had taken place and where one of the commanders had proposed to open the battle against the Mongols, but Muhammed II has chosen another way, dispersing his troops by garrisons throughout the towns, allowing the commanders to fight singly.

Despite a heroic defense of the city, its fate is sealed.

The town is destroyed and its population massacred and partially enslaved.

The one hundred thousand- to to one hundred and fifty thousand-man Mongol army, looting and destroying all cities that refuse to surrender, spares only artisans and engineers (whom they recruit, eventually taking them back to their tent-capital at Karakorum to help construct their civilization) as it shatters Otrar and …

…Khojend.

After subjugating those cities not totally destroyed by them, the Mongols permit their inhabitants to rebuild and resume trade.

Many of the towns in the oasis never recover and are abandoned.

During the invasion of Transoxania in 1219, along with the main Mongol force, Genghis Khan uses a Chinese specialist catapult unit in battle.

They will be used again in 1220 in Transoxania.

The Chinese may have used the catapults to hurl gunpowder bombs, since they already have them by this time.

While Genghis Khan is conquering Transoxania and Persia, several Chinese who are familiar with gunpowder are serving with Genghis's army.

Historians have suggested that the Mongol invasion brought Chinese gunpowder weapons to Central Asia.

One of these was the huochong, a Chinese mortar.

Nuremberg was probably founded around the turn of the eleventh century, according to the first documentary mention of the city in 1050, as the location of an Imperial castle between the East Franks and the Bavarian March of the Nordgau.

The fortified town receives its charter as a free imperial city in 1219.

Prince Louis, who had returned to France in 1217 to resume a principal role in the Albigensian Crusade, leads another military expedition to southern France in 1219.

The Muslims, seriously alarmed by February 1219, offer peace terms that include the cession of Jerusalem.

King John and many of the crusaders are eager to accept, but Pelagio, supported by the military orders and the Italians, refuses.

William of Holland, after hearing this, leaves the crusade and sails for home.

The Knights of the Sword have been attempting to Christianize the peoples of the eastern Baltic, but by 1219 they are being hard pressed and turned to Denmark’s King Valdemar II for help.

Pope Honorius III, via the bishop of Riga, elevates Valdemar's invasion of Estonia into a crusade.

Valdemar raises an army and calls all of Denmark's ship to gather to transport the army eastward.

Once assembled, the fleet numbers fifteen hundred ships.

When the army lands at Reval, located on Tallinn Bay, an inlet of the Gulf of Finland, the chiefs of the Estonians, who have come under the influence of the Orthodox Russians, sit down with the Danes and agree to acknowledge the Danish king as their overlord.

A few of them allow themselves to be baptized, which seems a good sign.

While suing for peace, the vastly outnumbered Estonian-Russian forces are clandestinely building their troop strength.

While the Danes are attending mass three days later, thousands of Estonians launch a surprise five-pronged counterattack on the Danish camp on June 15, 1219.

Confusion reigns and things look bad for Valdemar's crusade.

Luckily for him, Vitslav of Rügen gathers his men in a second camp and attacks the Estonians from the rear.

After destroying Reval, Valdemar builds a fortress on the site—called Tallin, which means "Danish castle" in Estonian—garrisoning it with soldiers to enforce conversion to Western Christianity.

The legend traces the origin of the Danish national flag, a white cross on a red field, to this encounter, called Battle of Lyndanisse, also known as the Battle of Valdemar.

Although myth holds that it fell from heaven during the battle to give victory to the Danes, is probably based on the war flag of the Holy Roman Empire.

Quarreling Roman families force Honorius III to flee to Viterbo, Italy, in June 1219; Frederick reconciles the rebellious Romans with the Pope.

Andrew’s foreign policy is a total failure also.

His younger son, Coloman, who had been crowned King of Halych, is expelled from his kingdom in August 1219 by Prince Mstilav of Novgorod.

Andrew has to make peace with the Prince of Novgorod and he also engages his youngest son, Andrew, to one of his opponent's daughters.

Rastko (later canonized as St. Sava), the younger brother of Stefan II Nemanja, Grand Prince of Serbia, counters his brother's affinity to the Roman Catholic church by traveling in 1219 to Nicaea—refuge of the exiled patriarch of Constantinople—where he receives the title of autocephalous archbishop of Serbia.

Emperor Theodore Lascaris has meanwhile strengthened his ties to the Latin empire by taking as his third wife Maria, daughter of the empress Yolanda, and by proposing that Greek and Latin clergy meet in Nicaea to consider the reunion of the two churches.

In August 1219, Theodore makes a lucrative commercial agreement with the Venetians in Constantinople.