Which brings us to the Grimaldis. Their founding father was a Genoese statesman named Grimaldo who lived in the 1100s. His sons and grandsons became a maritime force to be reckoned with. Fearing that a rival family might become more powerful and take over Genoa, the Grimaldis entered into an alliance with their fellow Guelphs, the Fieschi family.* Military conflicts between families ensued. In 1271, Guelphs were banned from Genoa, and the Guelphic factions sought refuge elsewhere. The search for strategic locations included setting sights on the Rock of Monaco. The Guelphs made peace with the pope five years later, but several chose not to return but to stay in other locations where they could raise armies against future conflicts.
Tides turn, and in time the Ghibellines were exiled from Genoa. As Guelphs and Ghibellines took turns being exiled and needing headquarters elsewhere, the Rock of Monaco changed hands more than once. Then, on the night of 8 January, 1297, François Grimaldi and his cousin, Rainier I, approached the castle of Monaco, which was then in the hands of the rivals of the Grimaldis. But he did not approach in force; instead, the story says, he and his companions were dressed as friars.
When the gates were opened to admit the group of friars, however, swords appeared from under their robes, and the surprise attack allowed the Guelphs to take over the castle. The coat of arms of the ruling family of Monaco commemorates this event by depicting two monks with swords.
Sadly for François, his marriage produced no heirs. He did not, therefore, establish a dynasty. In fact, the Grimaldis were driven out of Monaco a few years later. They returned, however, and re-took it by force this time. After François died, Rainer I, the cousin who accompanied him on his Trojan Horse raid, became the first sovereign Grimaldi ruler of Monaco and began the dynasty whose descendant made a star into a princess.
*The Guelphs were a faction that supported the Pope's interests over those of the Holy Roman Emperor; supporters of the HREmperor were known as Ghibellines.