The mission 1 of the 2. campaign of "Cossacks-The Art of War" (Under the flag of King Frederick – Trade Route Battle) is one of the most difficult missions of this game, and since no walkthru can be found in the internet (anymore) I will publish one here in my blog, after initially I thought this mission is impossible to win. I have found one reference to this mission here , mentioning it got Cossacks a lot of negative fan mail
At the beginning it is important to find the right route to the settlement at the coast in the south. The one resident a bit further down in the south should not be followed: he will get you into a trap. Instead head to the east to reach a larger village there. Even this route will get you into some skirmish, but only with swordsmen the Prussian pikeman can handle easily, and with some gunmen who will decimate your little troop a bit . Therefore you always should keep the officer and the three horses in the background. It is important to bring all three horses to the settlement in the south, to ensure later on when attacking the Austrians on the island enough coal and iron is available to fire your weapons.
After some time you reach the village in the east. If you are friendly to their leader the gates will open and let you pass thru towards the south. Soon you make it to the coast where you run into more swordsmen you have to fight your way thru, then you turn west and follow the coast to reach the settlement there.
There you must resist a massive attack, while the horses will be unloaded. You get the commandership of the settlement and this gets you additional pike- and gunmen. The cavalier approaching from the west you best attack right away with your pike- and gunmen, especially also since the cannons on the mountain in the west take down your fences there, Then it is a good idea to withdraw into the settlement, while more mobs attack from north. The two towers in the north will get them into some trouble, and you can add to that by using your howitzers, which you also got recently. At some point start attacking with your gun- and pikemen, but be careful: you will need a sufficient number of units for the real mission objective, the expulsion of the Austrians from the island in the southeast.
After finally you have withstand the attack you start attacking the island in the southeast using the three warships you got as well. First destroy the four towers and especially also the two block houses on the beach. A landing there is still almost impossible or a suicide mission. It took a while until I discovered that you can land in the north at the cliff line where one of the towers was located before.
So: distribute remaining units on the two ferries; the boarding only works outside of the Prussian settlement! With the first ferry land your units at that location mentioned before. Wait until the two cannons have fired to avoid big loss, then get out. Now quickly overpower the soldiers out there and gain the two cannons. With those and your three howitzers you got from the Prussian settlement, continue your attack against the settlement in the center of the island. The warships can provide assistance from north by using their artillery.
After you wiped out the folks in the settlement and gained their cannons finally it is time to deal with the remaining troops in the south of the island and get their cannons as well. Finished, game won!