Truce is the closest city to Guardia Castle and is considered the capital of the Kingdom. The area which would later become the city was first settled at or around the time of the Guardia Kingdom's creation; however, no information in-game is given as to an exact point in time. For over four hundred years, the Guardia Knights (the "Square Table" in the SNES release) has protected the Kingdom.
Between 580 and 600 A.D., the Kingdom came under attack during the War with the Mystics. While the town itself never saw conflict, the battles came dangerously close during the Battle of Zenan Bridge. After the war, the area which was previously Truce Canyon would be built upon to make Leene Square. Sometime later, Crono and Lucca would both be born in the town.
When the game first begins, Crono awakens in his house, situated in the northeast corner of Truce. The Truce of the Present contains a few more buildings than that of the Middle Ages, notably the Ticket Office, from which players can buy tickets to take the ferry to Porre on the southern tip of the continent. The Mayor's Manor, situated directly south of the Inn, features multiple non-player characters that inform starting players of game mechanics. In the original SNES release, talking to the Mayor again after learning about techniques will net 300 G.
According to the backstory for Chrono Cross, Porre began to amass a military before going on the offensive against Guardia. Guardia "lost" the battle, though to what extent we cannot be certain. What we know is that the forest was probably burned through; this action probably also occurred during an attack on Truce. Unfortunately, this occurred prior to the game's onset upon the conclusion of the game a new universe is born and no information is given as to whether these events still occur.