Year 1531 (MDXXXI) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. Events January–June January 26 – Lisbon, Portugal is hit by an earthquake, in which thousands die. February 27 – Lutheran princes in the Holy Roman Empire form an alliance known as the Schmalkaldic League. February or March – Battle of Antukyah: Ahmad ibn Ibrahim al-Ghazi of the Adal Sultanate defeats the Ethiopian army. April – Battle of Puná: Francisco Pizarro defeats the island's native inhabitants. April 12 – Askiya Musa is assassinated by his brothers in Songhai; Askia Mohammad Benkan is enthroned the same day. April 16 – The city of Puebla, Mexico, is founded. May – The third Dalecarlian rebellion in Sweden appears to be over, when the king accepts an offer made by the rebels, but violence flares up again the following year. June 24 – The city of San Juan del Río, Mexico, is founded. July–December July 25 – The city of Santiago de Querétaro, Mexico is founded. August 22 – Battle of Obertyn: The Moldavians are defeated by Polish forces under Jan Tarnowski, allowing the Poles to recapture Pokucie. August 26 – Comet Halley achieves its perihelion. October 11 – Battle of Kappel: The forces of Zürich are defeated by the Catholic cantons. Huldrych Zwingli, the Swiss religious reformer, is killed. October 28 – Battle of Amba Sel: Imam Ahmad ibn Ibrahim al-Ghazi again defeats the army of Dawit II, Emperor of Ethiopia. The southern part of Ethiopia thus falls under Imam Ahmad's control. November – Christian II`s invasion force arrives in Oslo. December 9 – The Virgin of Guadalupe first appears to Juan Diego at Tepeyac, Mexico City. December 12 – Mary, mother of Jesus, in the guise of Our Lady of Guadalupe, appears imprinted on the tilmàtli of Juan Diego Cuauhtlatoatzin, an Aztec convert to Catholicism, in Tepeyac near Mexico City. Date unknown Andrea Alciato publishes the first part of his Emblemata. Conquistador Francisco de Montejo claims Chichen Itza as capital of Spanish-ruled Yucatán. The University of Sarajevo is founded by Gazi Husrev-beg. Kõpu Lighthouse is completed. An enormous drought in Henan province, China, coupled with a gigantic swarm of locusts in the summer, forces many in destitute agricultural communities to turn to cannibalism instead of dying by starvation. Charles V, Holy Roman Emperor abolishes the worst abuses of the encomienda system, by pressure