The Hollow Months

The calendar in the Reach has fourteen months. Twelve are ordinary. The two in deep winter are the Hollow Months, when debts don't accrue, oaths can't be sworn, and the Wall hums loudest. Nobody agrees why. I invented the Hollow Months to solve a plotting problem: I needed the expedition to leave in a hurry, and a debt that would stop growing in winter gave Corin a reason to run. It turned into one of the deepest threads in the series. That happens a lot with worldbuilding. A patch becomes a pillar.