Need Help with :Renaisance into Fantasy Time change

[Uruk]

Hello @ all

I need Help with my new Idea.
I will change the Renaisance into a Fantasy Time Era but i can´t change the Description.

I tested :

<GameData>
<Language_en_US>
<Update>
<Set Text="Fantasy Time"/>
<Where Tag="TXT_KEY_ERA_3"/>
</Update>
</Language_en_US>
</GameData>

But nothing happend.
Where is my fault?

Thanks for your help.