Complex sentence: One of those to receive a request for patronage was Lord Chesterfield, a noted patron of the arts, who responded by sending Johnson £10 but offering no further support to Johnson through the nine years it took him to compile the "Dictionary".
Split into simpler sentences: One of those to receive a request for patronage was Lord Chesterfield, a noted patron of the arts. Chesterfield sent Johnson £10 but offered no greater support to Johnson through the seven further years it took him to compile the "Dictionary".