Arnold's father was a successful businessman, and the family moved in the upper levels of Norwich society. He was enrolled in a private school in nearby Canterbury, Connecticut, when he was 10, with the expectation that he would eventually attend Yale College. However, the deaths of his siblings two years later may have contributed to a decline in the family fortunes, since his father took up drinking. By the time that he was 14, there was no money for private education. His father's alcoholism and ill health kept him from training Arnold in the family mercantile business, but his mother's family connections secured an apprenticeship for him with her cousins Daniel and Joshua Lathrop, who operated a successful apothecary and general merchandise trade in Norwich. His apprenticeship with the Lathrops lasted seven years.