Trademan's Sons Need Not Apply

In Henry Chupack's book about Roger Williams, the founder of Rhode Island and a member of the first Baptist church in the USA, the following is said:

"...Williams, now twenty-five, had fallen in love with and wished to marry Lady Joan's niece, Jane Whalley. But because of his background as a trademan's son, Roger's suit was repulsed by the aunt, who apparently sought a suitor from a higher social level. Despite a serious illness suffered as a consequence of his rejection, the young clergyman soon recovered and found love elsewhere."