Kerry's paternal grandparents, shoe businessman Frederick A. "Fred" Kerry and musician Ida Lowe, were immigrants from the Austro-Hungarian Empire. Fred was born as "Fritz Kohn" before he and Ida took on the "Kerry" name and moved to the United States. Fred and Ida were born Jewish, and converted to Catholicism together in Austria. His maternal ancestors were of Scottish and English descent, and his maternal grandfather James Grant Forbes II was a member of the Forbes family, while his maternal grandmother Margaret Tyndal Winthrop was a member of the Dudley–Winthrop family. Margaret's paternal grandfather Robert Charles Winthrop served as the 22nd Speaker of the U.S. House of Representatives. Robert's father was Governor Thomas Lindall Winthrop. Thomas' father John Still Winthrop was a great-great-grandson of Massachusetts Bay Colony Governor John Winthrop and great-grandson of Governor Thomas Dudley. Through his mother, John is a first cousin once removed of French politician Brice Lalonde.

Who was Kerry's paternal grandmother?