sentences:  From 1993 to 1998 he was deputy chairman of the IG Metall.From 1998 until 2005, Riester was a member of the SPD's federal executive board, under the leadership of successive chairmen Gerhard Schröder and Franz Müntefering.From 1998 to 2002 Riester was Minister of Labour and Social Affairs in the cabinet of Chancellor Gerhard Schröder.