Almost every reigning hereditary monarch in Europe today can trace their lineage back to a few specific figures:

The history of Europe is often described not as a collection of separate nations, but as one massive, sprawling family tree. Because of centuries of strategic marriages, the current reigning monarchs of Europe—including King Charles III and King Felipe VI—are all related through a few key common ancestors. Key Common Ancestors

He is the most recent common ancestor of all current European monarchs.

House of Glücksburg (now Laborde de Monpezat through King Frederik X). Sweden: House of Bernadotte. Norway: House of Glücksburg. Netherlands: House of Orange-Nassau. Belgium: House of Saxe-Coburg and Gotha. Luxembourg: House of Bourbon-Parma. Liechtenstein: House of Liechtenstein. Monaco: House of Grimaldi. Where to Download Charts and PDFs

Often called the "Grandmother of Europe," her nine children married into nearly every major royal house, including those of Germany, Russia, Spain, and Norway.