The history of Monaco goes back to the 13th century. At the time of Gertrude, i.e. in the 12th century, this area belonged to the Duchy of Lombardy. Gertrud's husband Henry the Proud was not only Duke of Saxony and Bavaria but also of neighbouring Tuscany.
Is there a connection to Gertrude?
Caroline of Monaco married the descendant of Gertrud of Supplinburg and the Guelph Henry the Proud, namely Ernst August (born 1954), on 23 January 1999 in Monte Carlo in the palace of the Grimaldi family. He is Prince of Hanover, Duke of Brunswick and Lüneburg, Royal Prince of Great Britain and Ireland.
Detailed information can be found in the genealogical table of the Guelphs
The photo shows Ernst August Prince of Hanover with his second wife, Caroline (born 1957) Princess of Monaco. Monaco. On 20 July 1999 Princess Caroline of Hanover gave birth to her daughter Alexandra in Upper Austria.
The couple has since gone their separate ways, but they are still married (as of the end of 2014).