A Mongol envoy to Korea is murdered here in 1231, prompting Ögödei Khan, Genghis Khan’s son and the second supreme ruler (khakhan) of the Mongol empire, to order an invasion led by General Subutai.

Invading in 1231, Subutai’s forces secure the submission of the larger Korean cities and place Mongol governors in charge.

The mounting opposition to the Ch’oe, Koryo’s ruling military family, increases, causing the fearful puppet-king to flee.

Ögödei is determined to conquer the Henan holdings of the exceedingly rich Jin empire of the Jurzhen, the twelfth-century conquerors of northern China.

Ögödei, his brother Tolui, and General Subutai launch a two-pronged invasion in 1231: Ögödei and Subutai advance from the north and west to form a left wing; Tolui advances from the south with thirty-thousand men to form a left wing.

Tolui’s army meets no opposition until it reaches the mountains, and, although harried there by Jin forces, outmaneuvers them until the Jin withdraw to their capital, Kaifeng, where the remainder of the Mongol forces await.

The Latins, fearing Bulgaria's growing power, repudiate the treaty, and Baldwin is betrothed to the daughter of John of Brienne, titular king of Jerusalem, who is invited to Constantinople to be regent and elected coemperor-regent for life in 1231, thus voiding voiding the regency of John II of Nicaea.

Baldwin is to rule the Asiatic possessions of the empire when he reaches the age of twenty, is to marry John's daughter Marie, and on John's death is to enjoy the full imperial sovereignty.

A large Mongol force, dispatched in 1230 by Khakhan Ögödei to crush the Khwarezmian leader Jalal ad-Din in western Mesopotamia, surrounds him at Diyarbakr in 1231, but their quarry escapes, only to die in Kurdistan later in this year.

Iltutmish builds Sultan Ghari, the first Islamic mausoleum in Delhi, for Prince Nasiru'd-Din Mahmud, his eldest son, in 1231.

The crypt or the tomb is implanted in a Ghari (cave), approached by winding steep stairs made of stone, and supported by pillars and flooring.

The cave is covered by an unusual octagonal roof slab.

The exterior of the tomb structure built in Delhi sandstone with marble adornment exhibits a walled area with bastions (towers) on corners, which impart it the look of a fortress in aesthetic Persian and Oriental architecture.

The imperial marshal, Richard Filangieri, is able to establish himself in Jerusalem and Tyre, which he had regained by treaty in 1229, but not in Beirut or the capital in Acre.

The Constitutions of Melfi, promulgated by Frederick II for the Norman kingdom of Sicily in 1231, are Frederick’s outstanding pieces of legislation, part of his efforts to organize the government of Sicily, whose greater freedom he prefers, into unparalleled centralized efficiency.

The Establishment of the Papal Inquisition and the Role of Robert le Bougre (1231 CE)

In 1231, Pope Gregory IX formally instituted the papal Inquisition, creating a permanent Church tribunal to root out heresy. As part of this effort, he appointed Dominican friar Robert le Bougre as a special inquisitor in Burgundy, entrusting him with the task of identifying and prosecuting heretics.

Robert le Bougre: The “Hammer of Heretics”

• Robert le Bougre, whose name means "Robert the Bugre", was originally a Cathar himself before converting to Catholicism and becoming a Dominican friar.
• Due to his zeal in persecuting heretics, he earned the infamous title "Malleus Haereticorum" (Hammer of Heretics).
• He was notorious for his extreme severity, ordering mass burnings of heretics, particularly in Burgundy and northern France.

The Inquisition Under Gregory IX

• Pope Gregory IX centralized and expanded the Inquisition, moving it away from local episcopal courts to a more organized papal institution.
• The Dominicans were given primary responsibility for conducting inquisitions due to their rigorous theological training and devotion to orthodoxy.
• The Inquisition targeted Cathars, Waldensians, and other groups considered heretical.

Robert le Bougre’s Ruthless Campaigns

• Robert led severe inquisitorial proceedings in Burgundy and northern France, ordering large-scale executions.
• His brutality led even some Church officials to question his methods, and he was eventually removed from his position in 1239.

Legacy of the Papal Inquisition and Robert le Bougre

• The Papal Inquisition established a long-lasting institutional framework for heresy trials, which would later evolve into the Spanish and Roman Inquisitions.
• Robert le Bougre became infamous for his fanaticism and excessive cruelty, embodying the harshest aspects of medieval inquisitorial practices.
• The Inquisition, while initially focused on Catharism and other medieval heresies, would expand over the following centuries to target a wide range of religious dissenters.

The institution of the papal Inquisition in 1231 and the appointment of Robert le Bougre as an inquisitor in Burgundy marked a significant escalation in the Church’s efforts to suppress heresy, reinforcing papal authority over religious orthodoxy in medieval Europe.

Mongol hordes besiege the town of Kaifeng, beginning in 1232, but the townsfolk initially repulse them with "arrows of flying fire.” Tied to the shafts are tubes containing an early form of gunpowder, which produces a fiery exhaust.

A contemporary manuscript describes them as "making a noise like thunder" and "traveling a great distance," implying that these first rockets are not purely incendiary devices.

Ivan, thus betrayed by the Empire, hereafter separates the Bulgarian church from Rome.