Melessa Tarly

"My mother used it for sewing. She'd let me sit with her in her chamber, while she sewed, and read to her. My father put a stop to it, when he found out."

- Samwell Tarly giving Gilly a thimble

Melessa Tarly née Florent is an unseen character mentioned by Samwell Tarly in the first and second season although not by her name.

Background
Lady Melessa of House Florent is the wife Lord Randyll Tarly of Horn Hill and mother of Samwell Tarly of the Night's Watch. She is a cousin of Selyse Florent, the wife of Stannis Baratheon, and Ser Imry Florent.

Season 1
When Jon Snow asks Samwell what he is doing at the Wall, Samwell tells him that his father did not think him manly enough to inherit his title and lands so he forced him to join the Night's Watch or he implied that he would kill him and tell Melessa that it was a hunting accident.

Season 2
Before leaving Craster's Keep, Samwell Tarly gives Gilly a thimble that once belonged to Lady Melessa. He explains that he used to read to her while she was sewing but that his father ended the practice when he found out. He reveals that the thimble is the only possession he has from her and that it was a gift given when he left for the Wall.

In the books
In the A Song of Ice and Fire novels, Melessa Florent is a daughter of Lord Alester Florent, head of House Florent and Lord of Brightwater Keep, and Lady Melara Crane. She's the mother of Samwell and Dickon Tarly.

Melessa is a first cousin of Selyse Baratheon, as Melessa's father Alester is the older brother of Selyse's father Ryam. This also makes Sam the second cousin of Stannis Baratheon's daughter, Shireen Baratheon.