This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2009)

The 1150s decade ran from January 1, 1150, to December 31, 1159.

[edit] Events and trends

• Peter Lombard writes his Sentences.
• Eric the Saint, king of Sweden led the first Christian crusade to Finland.
• The Synod of Kells-Mellifont established the present diocesan system of Ireland (with later modifications) and recognzed the primacy of Armagh.