What did Miss Bingley tell Elizabeth about the grudge between Wickham and Darcy

Miss. Bingley tells Elizabeth that the "grudge" was not of Darcy's making, and that all is not as it appears. Ahe warns her that although she doesn't know the details, Darcy is not to blame. 

Let me recommend you, however, as a friend, not to give implicit confidence to all his assertions; for as to Mr. Darcy's using him ill, it is perfectly false; for, on the contrary, he has always been remarkably kind to him, though George Wickham has treated Mr. Darcy in a most infamous manner. I do not know the particulars, but I know very well that Mr. Darcy is not in the least to blame, that he cannot bear to hear George Wickham mentioned, and that though my brother thought that he could not well avoid including him in his invitation to the officers, he was excessively glad to find that he had taken himself out of the way.