The 1578 Battle of Alcácer Quibir is an interesting case of unintended consequences. The product of a Portuguese attempt to exploit a succession crisis in Morocco, its outcome actually helped create a succession crisis in Portugal. The situation in Morocco was a pretty straightforward usurpation. The Bani Zaydan, also known as the Saadis, were the dynasty that ruled either part or all of Morocco for about 100 years, gaining control over southern Morocco in the first half of the 16th century and then extending its dominion over all of Morocco through the first half of the 17th century. Under Muhammad al-Shaykh (d. 1557) they were able to eliminate both the Ottoman-backed Wattasid Dynasty of northern Morocco and the Portuguese colonial presence in coastal cities/fortresses like Agadir, Asilah, and the place where this battle was fought, al-Qasr al-Kabir (or Alcácer Quibir for the Portuguese).
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