An envoy from Song China had arrived at the court of the Mongols before the Mongolian–Jin War had escalated, a, perhaps to negotiate a united offensive against the Jin Dynasty.

Although Genghis Khan had refused, before dying in 1227 he had bequeathed a plan to attack the Jin capital by passing through Song territory.

A Mongol ambassador was subsequently killed by the Song governor in uncertain circumstances.

Before receiving any explanation, the Mongols had marched through Song territory to enter the Jin's redoubt in Henan.

In 1233, the Song Dynasty finally becomes an ally of the Mongols, who agree to share territories south of the Yellow River with the Song.

Subutai—Tolui having died in 1232 during the expedition—directs the siege of Kaifeng, surrounding the city’s forty-mile circuit of defensive walls with a second set of walls for siege engines, liquid fire balls, and gunpowder-aided projectiles.

Starvation and plague within the invested capital further help Subutai, now aided by Song warriors.

The Commune of Acre is able to relieve the siege of Beirut, but in John’s absence from Cyprus, the supporters of the Lusignans have taken control.

In any case, Henry I of Cyprus comes of age in the same year, and John’s regency is no longer necessary.

When Henry I succeeds to the throne, both John and Riccardo immediately race back to Cyprus, where on June 15 the imperial forces are defeated in battle.

Henry becomes undisputed king of Cyprus, and since he supports the Ibelins over the Lusignans, John's family remains influential.

The Castello Svevo (Swabian Castle), a castle in the Apulian city of Bari, Italy, probably built in 1132 by Norman King Roger II, had been destroyed in 1156 by king William I of Sicily; Emperor Fredrick II rebuilds and reinforces it in 1233.

The First Building Campaign of Amiens Cathedral (1220–1233): The Construction of the Nave and Transept

The first major building campaign of Amiens Cathedral, a masterpiece of High Gothic architecture, lasted until 1233 under the supervision of Robert de Luzarches. This phase focused on the construction of the nave and transept, establishing the foundation for what would become one of the largest and tallest Gothic cathedrals in Europe.

The Role of Robert de Luzarches (1220–1233)

• Luzarches was the chief architect responsible for the early stages of construction, emphasizing monumental scale, structural innovation, and spatial unity.
• His work set the soaring proportions of the cathedral, with a vault height of 138 feet (42 meters)—among the highest of any medieval cathedral.
• The nave and transept were completed under his direction, showcasing:
  • A spacious, light-filled interior, characteristic of the High Gothic style.
  • Tall clerestory windows, allowing for abundant natural light.
  • Strong vertical emphasis, with uninterrupted vaulting shafts leading the eye upward.

Transition to Thomas de Cormont (c. 1233 Onward)

• After Luzarches’ departure or death, Thomas de Cormont took over as master builder.
• His main contributions were:
  • The construction of the lower parts of the choir and apse.
  • Further refinements in the ribbed vaulting and support systems.
  • Continuing the harmonization of architectural elements, ensuring structural continuity.

Legacy of the Early Building Phases

• The nave and transept of Amiens Cathedral, completed by 1233, set the stage for the completion of the choir, apse, and facade in later decades.
• The cathedral remains a landmark of High Gothic architecture, influencing subsequent cathedrals in France and beyond.
• Luzarches and de Cormont’s contributions ensured that Amiens became one of the most structurally daring and artistically refined cathedrals of the Middle Ages.

The first construction phase of Amiens Cathedral (1220–1233) laid the foundation for its status as one of the greatest achievements of medieval Gothic architecture, combining unparalleled verticality, luminosity, and structural elegance.

Korean potters manufacture high-quality green Koryo ware.

In 1234, Koreans invent a new printing system with moveable type, allowing the ready dissemination of Buddhist and Confucian writings.

The Jin emperor flees in 1234, sacrifices his wives, and hangs himself.

After the victorious besiegers enter Kaifeng, Ögödei’s Chinese advisor Yeh-lü Ch'u-ts'ai directs the saving of both valuable artifacts and buildings, obtains mercy for scholars and peasants, and prevents wanton looting and slaughter.

The remaining Jurzhen withdraw to Manchuria (where they will eventually become known as Manchus).

Song general Meng Gong defeats the Jin general Wu Xian and directs his troops to besiege the city of Caizhou, to which the last emperor of the Jurchen has fled.

With the help of the Mongols, the Song armies are finally able to extinguish the Jin Dynasty that has occupied northern China for more than a century.

Dominic is canonized in 1234; this same year, Pope Gregory IX has the papal decretals on canon law collected and published as the “Decretales,” in 1234.

Theobald IV, Count of Champagne, succeeds his uncle Sancho VII of Navarre as King of Navarre in 1234.

In Pamplona at the time of Sancho's death, the new monarch, as Theobald I, immediately affirms the fueros of the realm.

This greatly increases his resources (not to mention his prestige), and the remaining years of his rule will be peaceful and prosperous.