diff --git a/doc/examples/make_circulant.cpp.preamble b/doc/examples/make_circulant.cpp.preamble
new file mode 100644
index 0000000..e575cce
--- /dev/null
+++ b/doc/examples/make_circulant.cpp.preamble
@@ -0,0 +1,4 @@
+#include <Eigen/Core>
+#include <iostream>
+
+template <class ArgType> class Circulant;