The Arendellian soldiers have been trapped in the Enchanted Forest for 34 years in Disney’s Frozen II.
The soldiers entered the forest during the conflict between Arendelle and the Northuldra. After the battle, the forest’s magical mist sealed the area, leaving both the soldiers and the Northuldra unable to leave. Their extended isolation explains why Lieutenant Mattias and his companions do not know what has happened in the outside world.
The number is stated during the film when the characters discuss the time that has passed. It is a useful timeline detail because Frozen II takes place after the events of the first Frozen, while still linking the sisters’ present to their parents’ generation.
The figure is not the same as the number of years Elsa spent isolated in her room, which is a different detail from the first film. The 34-year period specifically concerns the soldiers’ captivity in the forest.