+**664** can refer to the [year](/wiki/Year) 664 AD, a pivotal period in early medieval history. It notably marks the [Synod of Whitby](/wiki/Whitby_Synod), a significant event for the Christian Church in England.
+## See also
+- [Number](/wiki/Number)
+- [Chronology](/wiki/Chronology)
+- [Early Middle Ages](/wiki/Early_Middle_Ages)
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