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The 1140s decade ran from January 1, 1140, to December 31, 1149.

[edit] Events and trends

• Abbot Suger rebuilds the monastery of St Denis outside Paris, seen as the initiation of the Gothic style.
• Gratian's Decretals reinvigorate study of canon law and civil law.
• 1142—End of the reign of Emperor Sutoku, emperor of Japan
• 1142—Emperor Konoe ascends to the throne of Japan
• 1143—Celestine II elected pope, Alphonse VII The King of Leon and Castille recognises Portugal as an independent Kingdom and Alphonse I of Portugal as it's King through the Treaty of Zamora
• 1144—Pope Celestine II is succeeded by Pope Lucius II
• 1146—Saint Bernard of Clairvaux preaches the Second Crusade at Vézelay, Burgundy
• 1145–1147—Second Crusade—Crusaders capture Lisbon from Muslims
• 1148—The Alexiad is written by the Byzantine historian Anna Komnene, daughter of Alexius I.