Bathilda Bagshot was an expert on wizarding history (not surprising, since she lived through so much of it), and one of Albus Dumbledore’s earliest correspondents. The two actually became friends when his family moved to Godric’s Hollow after his father was imprisoned for killing the Muggle boys who had tormented Ariana. She had read and was impressed by his article in Transfiguration Today, published while he was still a student at Hogwarts.
Seeing how lonely Albus appeared to be, Bathilda introduced him to her nephew Gellert (perhaps not her brightest idea), believing they would be good for each other. Many years later he was forced to duel his old friend, who had grown into a feared Dark Lord, and in defeating him he won the Elder Wand, perhaps the first person to win it without having to kill its previous owner, keeping it until Draco Malfoy disarmed him on the Astronomy Tower shortly before Severus Snape killed Albus (on Dumbledore’s previous orders). One wonders if Bathilda ever regretted introducing the two boys to each other that summer, or if she was glad that at least for a little while her nephew had a positive influence in his life, even if their friendship didn’t last.