From WordReference Forum:
"How come you changed your mind?" is very informal, and it means "Why did you change your mind?"
"How came you to change your mind?" is formal and rather old-fashioned, and it means "What was the sequence of events that led you to change your mind?"
"How came you to change your mind?" is formal and rather old-fashioned, and it means "What was the sequence of events that led you to change your mind?"
Here, for example, are questions posed in one trial in the Old Bailey in 1789:
How came you to go to her?
...
How came you to let them strip you?
...
How came you to let them take away your cloaths?
http://www.oldbaileyonline.org/brows...v=t17890114-58
Here is a question from the trial of Lizzie Borden in Fall River, Massachusetts in 1893:
How came you to keep the time she came in the morning?
http://www.law.umkc.edu/faculty/proj...testimony.html
Here is Dickens using the construction in Our Mutual Friend:
"Very well where you are! I am ashamed to have brough Mr. Headstone with me. How came you to get into such company as that little witch's?"
What I said was correct. While the structure "How came you to [verb]?" is today old-fashioned, it was in common use at one time, and had the meaning I gave for it.
How came you to go to her?
...
How came you to let them strip you?
...
How came you to let them take away your cloaths?
http://www.oldbaileyonline.org/brows...v=t17890114-58
Here is a question from the trial of Lizzie Borden in Fall River, Massachusetts in 1893:
How came you to keep the time she came in the morning?
http://www.law.umkc.edu/faculty/proj...testimony.html
Here is Dickens using the construction in Our Mutual Friend:
"Very well where you are! I am ashamed to have brough Mr. Headstone with me. How came you to get into such company as that little witch's?"
What I said was correct. While the structure "How came you to [verb]?" is today old-fashioned, it was in common use at one time, and had the meaning I gave for it.
There is a famous apocryphal story about a nervous lawyer who was appearing before the United States Supreme Court. The Chief Justice, wishing to know the history of the case, and how it had been appealed from a lower court, began by asking "How came you to be here today?" to which the confused lawyer responded "I came on the Baltimore and Ohio Railroad..."