Complex sentence: He also been Chair of Amnesty International in Norway, and Vice-Chair of the International Executive Committee of Amnesty International, which he was elected on to at the age of 23, the youngest ever to hold the position.
Split into simpler sentences: He also been Chair of Amnesty International in Norway, and Vice-Chair of the International Executive Committee of Amnesty International. He was elected on to Amnesty's IEC at the age of 23, the youngest ever to hold the position.