One of the most significant mares in the General Stud Book

Dam of Squirt (grandsire of Eclipse); of Grey Robinson, through which the maternal line of the family continues and dam of Regulus (1745 King's Plates Winchester, Salisbury, Nottingham, Canterbury, Lewes, Lincoln and Newmarket, 1746 King's Plate Newmarket, and Champion Sire 1754, 1755, 1756, 1757, 1761, 1763, 1765 and 1766); grandam of Lady Caroline (1744 King's Plate [mares] Hambleton, 1745 King's Plates [mares] Newmarket, The Curragh; grandam of Robinson Crusoe (1729 King's Plate York, 1730 King's Plate Newmarket);

and 5th dam of Tom Turf, high class winner of 14 races in Ireland, including 9 King's Plates

However, early published, certified, pedigrees for Regulus omit the Snake (sire of Sister to Old Country Wench) cross, so it is very possible that the dam of Grey Robinson, dam of Regulus, is not Sister to Old Country Wench but rather her dam, Grey Wilkes