The first  Racial Discoveries in a town are achieved in the following ways:

 The Racial Steed (Orc War Wolf, Dwarven Battle Mule, Elven Thoroughbred or Human Battlebred) crafting discovery is made after researching 20 crafting techs.

 The Racial weapon (Orcish Sword , Dwarven Battleaxe, Elven Sword or Human Traditional Sword) are  discovered after building a Swordsmith.

 After both of these are awarded for your town's starting race it is time to move this town to a second race.

 The Racial Steed is discovered in this city by its second owning race after a single Craft research.  I surmise that the act of finishing one crafting research causes the Discovery code to check if there are enough crafting researches finished to get the Discovery.  The city gets the credit for all the Discoveries finished under the previous owner and the Discovery is awarded.

 The act of building, or leveling, up a Swordsmith triggers the award of the Racial Weapon. 

 The third and fourth races are done in exactly the same way.

 There is no additional award for getting these 8 Discoveries in one city.  I will be crafting each item in case that unlocks something, though I don't expect it to.

Once the HOC Racial Discovery is completely figured out it might be fun to try and get four more in a town. On the other hand that is at least 4 more awakenings of Audrey!