| a river in eastern Massachusetts that empties into Boston Harbor and that separates Cambridge from Boston | sovereign of the Holy Roman Empire |
| the eldest son of Elizabeth II and heir to the English throne (born in 1948) | |
| French physicist and author of Charles's law which anticipated Gay-Lussac's law (1746-1823) | |
| king of the Franks and Holy Roman Emperor; conqueror of the Lombards and Saxons (742-814) | |
| son of James I who was King of England and Scotland and Ireland; was deposed and executed by Oliver Cromwell (1600-1649) | |
| King of England and Scotland and Ireland during the Restoration (1630-1685) | |
| as Charles II he was Holy Roman Emperor and as Charles I he was king of France (823-877) | |
| King of France who began his reign with most of northern France under English control; after the intervention of Jeanne d'Arc the French were able to defeat the English and end the Hundred Years' War (1403-1461) | |
| King of France from 1560 to 1574 whose reign was dominated by his mother Catherine de Medicis (1550-1574) | |