1228 CE
A year defined by the extraordinary Sixth Crusade of the excommunicated Emperor Frederick II, who achieved through diplomacy what previous Crusades had failed to win through warfare.
Geopolitics & Diplomacy
- Holy Roman Emperor Frederick II departed on the Sixth Crusade in June despite his excommunication, sailing to the Holy Land with a small army and relying on diplomacy rather than military force.
- Frederick II opened negotiations with the Ayyubid Sultan al-Kamil of Egypt, leveraging their prior diplomatic relationship and the sultan's own political difficulties with rival Muslim rulers.
Conflict & Security
- Papal forces invaded Frederick II's Italian territories while he was on Crusade, with Pope Gregory IX exploiting the emperor's absence to seize lands in southern Italy and Sicily.
Culture & Society
- Francis of Assisi was canonized as a saint on July 16 by Pope Gregory IX, just two years after his death, in recognition of his radical devotion to poverty and Christian charity.
- The estimated world population was approximately 373 million.
Climate & Environment
- Atmospheric carbon dioxide concentration was approximately 275 parts per million, as later confirmed by ice core analysis.