1000 A.D. to 1010 A.D.

Keystone T-2

-Lucca proposes that time travel is possible with a Time Egg, which utilizes 
miniature black holes. The first Chrono Trigger was a Time Egg. 
-Lucca knows of Kid's heritage, somehow. 
-Lucca composes a letter to Luccia and leaves it with her. 
*Lucca, at some points, demonstrates the ability to construct incomplete Time
Eggs.

From: Chronology