favourite military doctrine in (defensive) wars was a scorched earth policy combined with harassment of the advancing enemy using hit-and-run tactics and disruption of communication and supply lines, followed by a large scale ambush: a weakened enemy would be lured in a place where it would find itself in a position hard or impossible to defend. A general attack would follow, often with devastating results. The shattered remains of what was once the enemy army would be pursued closely and harassed all the way to the border and sometimes beyond. A typical example of successful employments of this scenario is the Battle of Vaslui. Towards the end of the 15th century, especially after the success of guns and cannons, mercenaries became a dominant force in the country's military. With the economic demands created by the stagnation of the Ottoman Empire, the force diminished and included only mercenaries such as the seimeni. The 1829 Treaty of Adrianople allowed Moldavia to again maintain its own troops, no longer acting as an auxiliary under strict Ottoman supervision, and assigned red over blue pennants (see Flag and coat of arms of Moldavia). Their renewed existence under Mihail Sturdza was a major symbol and rally point for the nationalist cause, aiding in bringing about the 1848 Moldavian revolution. Fleet An early mention of a Moldavian naval fleet is found in connection with the rule of Aron Tiranul, who used it to help Wallachian ruler Michael the Brave establish his control over the Chilia branch of the Danube and Dobruja. The Treaty of Adrianople provided for a Moldavian self-defense naval force, to be composed of caicque vessels. Schooners armed with cannons were first built in the 1840s. Along with patrolling the Danube, these made their way on its tributaries, the Siret and the Prut River. Geography Geographically, Moldavia is limited by the Carpathian Mountains to the West, the Cheremosh River to the North, the Dniester River to the East and the Danube and Black Sea to the South. The Prut River flows approximately through its middle from north to south. Of late 15th century Moldavia, with an area of , the biggest part and the core of the former principality is located in Romania (45.6%), followed by the Republic of Moldova (31.7%), and Ukraine (22.7%). This represents 88.2% of the Republic of Moldova's surface, 18% of Romania's surface, and 3.5% of Ukraine's surface. The region is