'''Pertempuran Winwaed''' ([[Bahasa Wales]]: ''Maes Gai''; {{lang-lat-med|[[Bahasa Latin Abad Pertengahan]]: Strages Gai Campi}}<ref>[[Annales Cambriae]] [B], [[s:la:Annales Cambriae B/VIII|p. 8]].</ref>) merupakan sebuah konflik yang berlangsung pada tanggal [[15 November]] [[655]]{{#tag:ref|Manuscript A of the ''[[Anglo-Saxon Chronicle]]'' gives the year as 655. [[Bede]] also gives the year as 655 and specifies a date, 15 November. R. L. Poole (''Studies in Chronology and History'', 1934) put forward the theory that Bede began his year in September, and consequently November 655 would actually fall in 654; Frank Stenton also dated events accordingly in his ''Anglo-Saxon England'' (1943).<ref>''The Anglo-Saxon Chronicle'', translated and edited by M. J. Swanton (1996), paperback, {{ISBN|0-415-92129-5}}.</ref> Others have accepted Bede's given dates as meaning what they appear to mean, considering Bede's year to have begun on 25 December or 1 January.<ref>S. Wood, "Bede's Northumbrian dates again", ''The English Historical Review'', Vol. 98, No. 387, April 1983, pages 280–296</ref> The historian D. P. Kirby suggested the year 656 as a possibility, alongside 655, in case the dates given by Bede are off by one year.<ref>D. P. Kirby, "Bede and Northumbrian Chronology", ''The English Historical Review'', Vol. 78, No. 308, July 1963, pages 514–27</ref> The ''[[Annales Cambriae]]'' gives the year as 657.<ref>[http://www.fordham.edu/halsall/source/annalescambriae.html Annales Cambriae at Fordham University]</ref>|group="notes"}} antara Raja [[Penda dari Mercia]] dan [[Oswiu|Oswiu dari Bernicia]], yang berakhir dengan kekalahan [[Mercia]] dan kematian Penda.<ref>{{cite news|last1=Selwood|first1=Dominic|title=On this day: Britain's last great pagan king is struck down by Christians at the Battle of the Winwaed|url=https://www.telegraph.co.uk/news/2016/11/15/on-this-day-britains-last-great-pagan-king-is-struck-down-by-chr/|accessdate=14 November 2017|work=The Telegraph|date=15 November 2016|subscription=yes}}</ref> Pertempuran tersebut menandai kematian efektif paganisme Anglo-Saxon.
