Year 939 (CMXXXIX) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar.
- Hugh the Great, count of Paris, rebels against King Louis IV ("d'Outremer") and gains support from William I, duke of Normandy. Hugh, along with Herbert II, count of Vermandois, Arnulf I, count of Flanders and William pays homage to King Otto I (ruler of the East Frankish Kingdom), and supports him in his struggle against Louis.
- July 19 – Battle of Simancas: Caliph Abd-al-Rahman III of Córdoba claims a Jihad ('Holy War') and raises an army of 100,000 men to end the Kingdom of León. He razes the cities of Medina del Campo, Ìscar and Alcazarén (previously abandoned by their population) and finally, reaches the city of Simancas (near modern-day Valladolid), where Christian forces under King Ramiro II wait for him. After three days, Ramiro defeats the Moorish army with an alliance of Castile and Navarre. Abd-al-Rahman orders a retreat along the Duero River, and is almost killed, due, most likely, to treason by Arab elements in the Moorish army.
- August 1 – Battle of Trans-la-Forêt: Bretons defeat Viking occupiers.
- August 5 – Battle of Alhandic: Abd-al-Rahman III defeats the garrison of those loyal to Ramiro II at Zamora, in the context of the Spanish Reconquista.
- October 2 – Battle of Andernach: Otto I crushes a rebellion against his rule, by a coalition of Eberhard III, duke of Franconia, and other Frankish dukes, in Andernach on the Rhine River. Otto prevails, with support from Odo of Wetterau. Eberhard is killed while Gilbert, duke of Lotharingia (or Lorraine) drowns when trying to escape.
- ^ The Annals of Flodoard of Reims; 919-966, Ed, & Trans. Steven Fanning & Bernard S. Bachrach (University of Toronto Press, 2011), p. 32.
- ^ "Abd-al-Rahman III". Encyclopædia Britannica. I: A-Ak - Bayes (15th .). Chicago, IL: Encyclopædia Britannica, Inc. 2010. pp. 17–18. ISBN 978-1-59339-837-8.
- ^ Kevin Halloran, "Anlaf Guthfrithson at York", pp. 180–185.
- ^ Nussbaum, Louis Frédéric et al. (2005). "Taira no Masakado" in Japan Encyclopedia, p. 926., p. 926, at Google Books.
- ^ Vo, Nghia. Legends of Vietnam: An Analysis and Retelling of 88 Tales, p. 52 (McFarland, 2012).