Which preposition to use with rickman

in Occurrences 3%

In a letter to Rickman in January, 1802, Lamb says that he is leaving the Post, partly on account of his difficulty in writing dramatic criticisms on the same night as the performance.

as Occurrences 1%

This would be Edward Phillips, who, I think, succeeded Rickman as secretary to Abbot (afterwards Lord Colchester), the Speaker.

Which preposition to use with  rickman