Springfield, IL (CAPITOL CITY NOW) – The Abraham Lincoln Presidential Library and Museum has obtained a letter that, officials there say, may seem familiar, especially if you’re a parent trying to get your kids adjusted to school right now.

This letter, otherwise previously unknown, is one written by Mary Todd Lincoln apologizing to son Tad’s teacher at the Chicago Academy for sending him back to school “without knowing his lesson in geography.”

“Taddie goes to school this morning, I am sorry to say, without knowing his lesson in geography. Illness last evening prevented my looking it over with him & he finds this a difficult geography,” she wrote in the letter.  “Please excuse him this time & oblige yours truly, Mrs. A. Lincoln.”

The letter is dated April 17, 1868, three years after Abe Lincoln’s death, and as Mary and Tad lived in Chicago — at the time, living in in a hotel that eventually was destroyed by the Great Chicago Fire.

“This letter humanizes Abraham Lincoln’s widow and son in a way that few other documents can match,” said Ian Patrick Hunt, the ALPLM’s head of acquisitions, in a news release. “It captures a perfectly ordinary moment that prompts us to think about Mary and Tad’s life after the assassination. Was Mary too ill to help with the homework because she was having another of her migraines? Was she incapacitated by grief? How was Tad adapting to a new school after the trauma of his father’s death?”

Tad Lincoln died in 1871, after he and Mrs. Lincoln had moved back to the U.S. from Germany for a time.

The letter was donated earlier this year.