kill two birds with one stone

Apparently coined by Dr. John Bramhall, Bishop of Derry, in a 1646 letter to Thomas Hobbes, later published in 1656. Compare earlier stop two gaps with one bush.

• "Biking to work kills two birds with one stone. It saves money travelling and will help to lose weight."
• "In favouring the well-connected, politically and culturally sophisticated Italian merchants and diplomats who regularly arrived in England on curial business Henry killed two birds with one stone, gratifying popes by the attention and respect shown to their intimates, and employing them as his own eyes and ears at Rome […]."

• feed two birds with one scone

• at one blast
• one fell swoop
• stop two gaps with one bush
• while one is at it