The second smallest state in the world Monaco is city state of 1,2 mile square.the country. Francesco Grimaldi seized the Rock of Monaco in 1297, starting the Grimaldi dynasty, under the sovereignty of the Republic of Genoa. The Grimaldis acquired Menton in 1346 and Roquebrune in 1355, enlarging their possessions. In 1338 Monegasque ships under the command of Carlo Grimaldi participated, along with those of France and Genoa, in the English Channel naval campaign. Plunder from the sack of Southampton was brought back to Monaco, contributing to the principality's prosperity until 1860. n 2002, a new treaty between France and Monaco clarified that if there are no heirs to carry on the dynasty, the Principality will remain an independent nation, rather than be annexed by France. Monaco's military defense, however, is still the responsibility of France.