The card Bribery was originally slated to be in Urza's Destiny, and had the playtest name "Kick-Ass Control Magic." But the Destiny team wanted to continue the "free mechanic" into that set, and created Treachery, which is basically a five mana "free" Control Magic.
Bribery was moved up a set into Mercadian Masques, where it found a happy home, and both cards made significant impacts on their respective Block Constructed -- and Standard -- metagames.
Later, Odyssey debuted Persuasion, which is Treachery without the free mechanic. The development teams believe the original Control Magic was undercosted at 4 mana, and Treachery was undercosted at 5, but both Bribery and Persuasion are costed correctly.