A situation came up in our last session of D&D 5e where another character wanted to use a single-handed weapon after using a two handed weapon attack.
She made the attack with a two handed weapon on one turn and wanted to draw her single handed weapon and attack with that on the next turn. She didn't want to drop the two handed weapon, but wanted to hold it in her off hand and attack with the single handed weapon in her main hand.
The Storyteller (which is what my group calls the DM) said she had to drop the two-handed weapon.
We argued that she wasn't attacking with it and just keeping it in her off hand as a carry item and the Storyteller wanted us to find a ruling on that specific use, as he was of the understanding that a two-handed weapon required two hands at all times.
Where can we find such rulings? Is there one?