Tibian levels represent the experience of a character. The more experience, the more levels a character will have. They gain experience by killing monsters or by completing certain quests, and with the experience comes the levels.
Every time you gain one level, you receive:
The amount of experience needed for the next level will increase for every level a character will get. As far as known there is no limit to the number of levels that can be gained.
When Eternal Oblivion reached level 270, there was a "tibia server database, level limit" that prevented him from gaining certain advancements for his level. This problem has been fixed.
On 6 March 2007, Mateusz Dragon Wielki was the first player to reach level 300.
On 24 December 2008, Lord'Paulistinha was the first player to reach level 400.