Childhood with Sam
Nathan Drake was born in the year of 1976 as Nathan Morgan, the second son of American archaeologist Cassandra Morgan and her husband, and the younger brother of Samuel Morgan, who was older than him by five years.
 
In 1981, when Nathan was five, his mother Cassandra had been suffering from an unknown terminal illness, which soon led to her suicide. Following the death of Cassandra, Nathan and Samuel's father decided to give up his hold on them and surrender his sons to the state. Not long afterward, both boys were entrusted to the Francis' Boy's Home, an orphanage ran by priests. All of their mother's possessions — including her archaeological works — were later sold by their father.
 
The two spent the next few years in the orphanage, during which Nathan took interest in books, all while learning free-running and climbing from Sam. While growing up to dislike most of the orphanage staff such as Sister Catherine, he did become fond of Father Ryan Duffy, calling him "the only decent guy there". Eventually, Sam was kicked out of the orphanage due to criminal activities, before taking a job to support both himself and Nathan.
 
Becoming Nathan Drake:
By the late 1980s, when Nathan was thirteen, he got in a fight one day with an older boy by the name of Edward after the latter teased him by grabbing one of his books and insulting his parentage, leading to Nathan being suspended from a retreat with the rest of the orphanage. After receiving a harsh lecture from Sister Catherine, Nathan noticed light signs by Sam and went to meet with him.
 
Meeting up with Sam, Nathan followed his brother out the orphanage's limits, before being presented with a motorcycle Sam bought him as a gift, which he realized was Sam's way to apologize; Sam then revealed his intentions to leave for at least a year due to his new job, much to Nathan's shock and dismay. Trying to cheer his younger brother up, Sam also revealed he tracked down their mother's possessions. The two then proceeded to plan on stealing them.
 
Breaking into the house containing their mother's writings, Nathan and Samuel were soon confronted by the buyer, Evelyn, an old woman revealed to be a friend and former employer of Cassandra; the retired adventurer revealed of Cassandra's past works prior to her death including her theory about Francis Drake's illegitimate heirs, as well as her research on Henry Avery. Having called the town guard earlier due to the Morgan brothers' break-in, Evelyn went to call them off, but soon died due to heart failure, prompting the Morgan brothers to escape the house.
 
After escaping, the two decided to honor their mother and her theory on Francis Drake's heirs by changing their names to Nathan and Samuel Drake. With this, the brothers would stick up together for the coming years.
 
Eventually, Nate ended up working for a treasure hunter, Victor Sullivan.