Which preposition to use with disavowal

of Occurrences 29%

The scene of negotiation was now removed to Madrid, and, in September, Mr. Harris was directed to demand, from Grimaldi, the Spanish minister, the restitution of Falkland's island, and a disavowal of Buccarelli's hostilities.

on Occurrences 2%

The note of that functionary communicates the answer to those inquiries, and may be deemed satisfactory, both from the denial of the fact that any such treaty has been concluded and from its positive disavowal on behalf of the British Government of the policy intended to be subserved by such treaties.

Which preposition to use with  disavowal