Lady Yvonne Rowlandson, Baroness Tweenriver, was a Manticoran peer of the realm and politician. In the early 16th Century PD, she was a member of the Committee for Military Sanity and a political ally of Earl Breakwater. (MA1) She was present for a meeting in Breakwater's office when the Volsung Mercenaries invaded the Manticore System in 1543 PD. (MA2)