A poll tax is a one-time tax or fee levied on an individual which entitles him to vote. It's primary application in that way was aimed at disenfranchising poor people when election time came. And it makes perfect sense that prejudicial people would do this to prevent slaves and others who were indigent from voting. The revenue wasn't very effective in any reconstructive efforts because it didn't net that much; it wasn't designed as a "real" source of revenue. There are other applications of this idea which were designed to raise money, and as they are followed back in history, they don't relate to voting. A land holder of old may go around to each village and demand one coin from a man for himself, and a coin for each member of his family. That would be a head tax, which is somewhat the same. All these taxes are uniform in nature. Wikipedia has information, and a link is privided.