A cocking system for a crossbow. A string carrier slides along the center rail during movement with the draw string in the released configuration to a retracted position that locates the draw string in the drawn configuration. A trigger is positioned to move the catch from the closed position and the open position to fire the crossbow when the string carrier is in the retracted position. At least one cocking rope is configured to engage with the string carrier to retract the string carrier and the draw string to the drawn configuration. A retaining mechanism retains the string carrier in the retracted position and the draw string in the drawn configuration independent of the cocking ropes.