I don't know about weight class, but two-handed recurve sabres were used in the Balkans in ancient times. The Thracians (who lived in what is now northern Greece, Bulgaria and European Turkey) used a massive sword of this type known as the rhomphaia, and the Romans encountered a very similar weapon in their wars against the Dacians (who lived in what is now Romania), which they referred to as the falx. Allegedly, the Romans reinforced their legionary helmet with additional metal strips and extended its neck guard to protect the infantry against blows from the falx.