Ben was married three times, each wife
giving him a son.
All three wives died leaving Ben to raise
"the boys" on his own.
Each wife was as different as the sons they produced.

His first wife, Elizabeth (episode 65: "Elizabeth, My Love"), was a New Englander and the mother of hard-headed, serious Adam.
Elizabeth died by the birth of her son and for Ben it was the reason to leave New England and search for a new home.

Inger (episode 95: "Inger, My Love") was Ben's second wife and the mother of the gentle giant Hoss.
Inger died during an Indian raid on their way to the west coast of America.

The third wife Marie (episode 120: "Marie, My Love") gave Ben his third son, the handsome and hot tempered Little Joe.
Marie is the only wife of Ben, who lived on the Ponderosa Ranch for quite some time. She died in a fall from a horse. Her grave is on the ranch, near Lake Tahoe.
At the end of the Bonanza show (episode 402: "A Home for Jamie") Ben adopted Jamie Hunter as his own son.
So in truth Ben had four sons!!
Together Ben and his sons defend the Ponderosa Ranch, their large ranch in Nevada, against all threats.
Ben-Lorne Greene-Cartwright sings on the record "Welcome to the Ponderosa" the story of his three beloved wifes in the song "Saga of the Ponderosa"
In Bonanza episodes you may notice, that Ben has a deep respect for his sons. On the record "Bonanza - Ponderosa Party Time" Ben Cartwright not only says it, but he also sings it!!