Festival of the Mother

The Festival of The Mother is a day dedicated to The Mother herself. It's presumably celebrated every year throughout King's Landing and the realm.

In 303AL,Tommen Baratheon scheduled Cersei Lannister and Loras Tyrell's trial at the Great Sept of Baelor. On the day of the Festival of The Mother in the capital, many gathered at the front of the Great Sept, shortly before it was destroyed by wildfire under the orders of Cersei.