diff --git a/Eigen/src/Geometry/Quaternion.h b/Eigen/src/Geometry/Quaternion.h
index 56fa2bfbf..32e7e76fa 100644
--- a/Eigen/src/Geometry/Quaternion.h
+++ b/Eigen/src/Geometry/Quaternion.h
@@ -739,8 +739,9 @@ template<typename Other>
 struct quaternionbase_assign_impl<Other,3,3>
 {
   typedef typename Other::Scalar Scalar;
-  template<class Derived> static inline void run(QuaternionBase<Derived>& q, const Other& mat)
+  template<class Derived> static inline void run(QuaternionBase<Derived>& q, const Other& a_mat)
   {
+    const typename internal::nested_eval<Other,2>::type mat(a_mat);
     using std::sqrt;
     // This algorithm comes from  "Quaternion Calculus and Fast Animation",
     // Ken Shoemake, 1987 SIGGRAPH course notes
diff --git a/test/geo_quaternion.cpp b/test/geo_quaternion.cpp
index 17229be4a..761bb52b4 100644
--- a/test/geo_quaternion.cpp
+++ b/test/geo_quaternion.cpp
@@ -49,6 +49,7 @@ template<typename Scalar, int Options> void quaternion(void)
   */
   using std::abs;
   typedef Matrix<Scalar,3,1> Vector3;
+  typedef Matrix<Scalar,3,3> Matrix3;
   typedef Matrix<Scalar,4,1> Vector4;
   typedef Quaternion<Scalar,Options> Quaternionx;
   typedef AngleAxis<Scalar> AngleAxisx;
@@ -101,6 +102,11 @@ template<typename Scalar, int Options> void quaternion(void)
   q2 = q1.toRotationMatrix();
   VERIFY_IS_APPROX(q1*v1,q2*v1);
 
+  Matrix3 rot1(q1);
+  VERIFY_IS_APPROX(q1*v1,rot1*v1);
+  Quaternionx q3(rot1.transpose()*rot1);
+  VERIFY_IS_APPROX(q3*v1,v1);
+
 
   // angle-axis conversion
   AngleAxisx aa = AngleAxisx(q1);