Thomas Jefferson and Abigail Jefferson had a troubled personal history

The men who would become America's second and third presidents started as diplomats in Paris during the summer of 1784, and their friendship flourished there. Abigail traveled across the Atlantic because she was sick of writing to her husband from afar.

Jefferson and Mrs. Adams initially became friends through their mutual interest in gardens and songbirds. Abigail and her new acquaintance unwillingly broke up when John was appointed Ambassador to the Court of St. James in London ("I shall regret the loss of Mr. Jeffersons Society," she wrote). They started sharing rumors and even occasionally sending each other gifts as they became worldwide pen buddies. She was, in Jefferson's words, "one of the most estimable personalities on earth," as he once revealed to James Madison.

Sadly, their friendship deteriorated after Mr. Adams suffered a crushing election setback at the hands of Jefferson in 1800. Abigail sent a thoughtful note of sympathy when the new President's daughter, Polly, passed away at age 25 four years later. The letter moved Jefferson and impressed him as well. She even ended it with the wishes "of her who formerly took pleasure in proclaiming herself your friend," he noted, "carefully avoiding a single [word] of friendship towards myself."

Their relationship didn't warm up until 1811 when Jefferson and her husband started communicating again. The Sage of Monticello and Abigail would then pick up their letter-writing again.