cup-bearer

A cupbearer was historically an officer of high rank in royal courts, whose duty was to pour and serve the drinks at the royal table. On account of the constant fear of plots and intrigues, a person had to be regarded as thoroughly trustworthy to hold the position. He would guard against poison in the king's cup, and was sometimes required to swallow some of the drink before serving it. His confidential relations with the king often gave him a position of great influence.