1231

Events

 * becomes bishop of.
 * Emperor promulgates the  (also known as Liber Augustalis), a collection of laws for.
 * launches a campaign against the Norman lordships in.
 * troops pours across the.

Births

 * - of Japan (died )
 * , Chinese astronomer and mathematician
 * (died )
 * (died )

Deaths

 * -, Portuguese saint (born )
 * - of Japan (born )
 * -, daughter of and saint (born )
 * , Arab physician and traveller
 * , Arab physician and traveller