clue:- Albigensians go to Isaiah for purification (9) C?T???S?? CATALYSIS? If so why? clue:- Was obliged to be taken round Egyptian capital (4) ?E?D. clue:- Retreat from a Saint Petersburg museum (9) ??R?I?A?E. clue:- Roman bones found in a Greek mountain (4) ?S??. Thanks in advance.