diff --git a/modarith.h b/modarith.h
index c473e3d0..bd68f012 100644
--- a/modarith.h
+++ b/modarith.h
@@ -57,7 +57,7 @@ public:
 	/// \brief Copy construct a ModularArithmetic
 	/// \param ma other ModularArithmetic
 	ModularArithmetic(const ModularArithmetic &ma)
-		: m_modulus(ma.m_modulus), m_result(static_cast<word>(0), m_modulus.reg.size()) {}
+		: AbstractRing<Integer>(ma), m_modulus(ma.m_modulus), m_result(static_cast<word>(0), m_modulus.reg.size()) {}
 
 	/// \brief Assign a ModularArithmetic
 	/// \param ma other ModularArithmetic