system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Where did all the last names come from? 

Who made them all up? I know people used to be named according to their home, like Jesus of Nazareth, but where did all of the ones in existence today come from? How are new last names added over time?
gpt
There are many naming traditions throughout the world. 

Many English names reflect jobs. Remember that before public schools existed, boys (who spread the last name) would generally become apprentices of their father and learn his trade, take over after his death and teach their own sons, and so on. So it made sense for a person's last name to reflect their occupation, because the occupation was also hereditary.

This is where we get names like John *Carpenter*, Sue *Gardener*, Robert *Plant*, James *Cook*, Anna *Smith*, and so on. Some of these jobs no longer exist; a cooper was someone who made barrels, a fletcher was someone who made arrows, a thatcher was someone who made rooves, and those are all common surnames. 

Some names still reflect places, like George Washington (where 'ton' is *town*, George from Washing-town).

Other names reflect the name of the father; Thomas *Jefferson* (Jeffery's-son), Jack *Williamson* (William's-son), and so on. In Iceland, this actually applies directly to the parent, rather than carrying one name perpetually; Bjork's last name is Guomundsdottir (Guomond's-daughter), and her child could be called Karen Bjorkdottir (Bjork's-daughter), and her grandson could be Bjorn Karenson (Karen's-son), etc.