Murrah ibn Ka'b

[1] He was the sixth-in-line of Muhammad's grandfathers.

He is the common ancestor of all four of Muhammad's grandparents.

He is also the common ancestor of six of Muhammad's eight great-grandparents.

He is also the common ancestor of Muhammad and his friend Abu Bakr.

His mother was Wahshiya bint Shaiban ibn Muharib ibn Fihr ibn Malik, so his mother was a second cousin of his father.