My gr. gr grandmother was Lousia Slack sister of Ann E. Slack who married Giles Alleger .I have a link to the Slack family tree it is awesome well documented . I believe the Alleger /Allega families of Linn and Chariton Co. are all descended from an Allegre family ,there is a well documented family tree for this family .They were in Madison and Garrard co. Ky. The name was spelled various ways in records. A sister Sarah Allegre came to Linn abt 1880 to live with her son a "Roberts" She had brothers William, Robert John and James ,Robert was in Linn co.