In the year AD 1406...
- The Hundred Years War drags on into its 70th year. The French recapture Lourdes from the English after an 18-month siege.
- In England, King Henry IV faces off with the longest Parliament of the Medieval period (156 days) over Parliament's demands that he return some crown lands and spend more tax revenue on national defense. The crisis is ultimately resolved, but Parliament secures some precedent-setting new powers over royal appointments and crown expenditures.
- Following the death of his father Robert III, the child-king James I of Scotland attempts to flee to France but is captured by the English en route and held captive until 1424.
- When the emmissaries of China's Yongle Emperor to Annam (Vietnam) are murdered, a massive Chinese army of 200,000 men invades and subdues Annam, ending the Tran Dynasty and paving the way for Vietnam to become a tributary state of China the following year.
- Florence conquers Pisa, at long last securing access to the sea.
- The Burmese conquer Arakan, forcing Arakanese king Naramakhbala to flee and take refuge with Sultan Nasiruddin Shah in Bengal, where he would become a Muslim, and later would return to Burma and restablish Arakan as an Islamic state.
- Korean king Taejong continues his father Taejo's assault on wealthy Buddhist temples, suppressing all but 242 temples nationwide by confiscating the temples' lands and slaves.
- French reformist abbess Saint Colette forms the Colettine Poor Clares branch of the Poor Clares order of nuns following a vision Saint Francis commanded her to restore the Poor Clares to the original severity of poverty vows.
- The English crown grants the entire Isle of Mann to Sir John Stanley, whose family would rule it uninterruptedly until 1736. The Stanleys refused to be called "kings" and instead adopted the title "Lord of Mann,” which they still hold.
- China's Yongle Emperor begins construction on the Forbidden City in Beijing.
- Spanish diplomat Ruy González de Clavijo returns to Spain from his diplomatic mission to the court of Timur and pubishes his valuable account of his voyage, Embassy to Tamerlane (Embajada a Tamor Lán).
- Chinese physician Zhu Xiao pulishes his Jiuhuang
Bencao ("Materia Medica for Famine"), a compilation of novel ways to gain sustenance from plants not ordinarily thought of as food.
- Chinese physicians Zhu Su and Teng Shuo publish the Puji Fang ("Prescriptions for Saving the Public") a massive collection of 61,739 medical prescriptions for all manner of ailments.
- English poet Thomas Hoccleve's poem La Mâle Règle ("The Male Regimen") presents a vivid picture of the delights of a bachelor's life in the taverns of Westminster.
These people were born in 1406:
These people died in 1406:
- The great Arab historian Ibn Khaldun.
- Henry III, king of Castile and León, succeeded by his newborn son John II.
- Scottish king Robert III, succeeded by his son James I.
- Pope Innocent VII, succeeded by Pope Gregory XII.
- Florentine humanist scholar Coluccio Salutati.
- Influential Dutch sculptor Claus Sluter.
- Francesco II, the "tyrant of Padua," strangled by the Venetians for "treason."
- Al-Mutawakkil I, the Abbasid caliph of Cairo, succeeded by Al-Musta'in.
- William of Austria, Duke of Carinthia, Styria, and Carniola.
1405 - 1406 - 1407