Battle for Solitude

Background
Alongside Ulfric Stormcloak, Galmar Stone-Fist and an army of Stormcloak warriors, the Dragonborn leads to pursue General Tullius to surrender to the Stormcloak Rebellion.

Ulfric's speech
Outside of Castle Dour Ulfric will begin his rousing speech:

"This is it men! It's time to make this city ours! We come to this moment carried by the sacrifices and the courage of our fellows. Those who have fallen. And those still bearing the shields to our right.

On this day, our enemy will witness the fullness of our determination, the true depth of our anger and the exhalted righteousness of our cause. The gods are watching. The spirits of our ancestors are stirring. And the men under suns yet to dawn will be transformed by what we do here today. Fear neither pain, nor darkness.

For Sovngarde awaits those who die with weapons in their hands, and courage in their hearts. We now fight our way to Castle Dour to cut the head off the legion itself! And in that moment, the gods will look down and see Skyrim as she was meant to be. Full of Nords who are mighty, powerful, and free! Ready now! Everyone, with me! For the sons and daughters of Skyrim!

Objectives
Note: It is entirely possible to "grind" skills, with this battle. As long as the Dragonborn does not kill the archers on top of the roofs just before the General is encountered, Imperial soldiers will continue to spawn in the courtyard. This can be quite useful to level combat skills. However, do not accidentally attack Ulfric or Galmar too many times, as this will cause them to become hostile. (Remember that when you grind levels fast, the game does as well, so all the NPCs and monsters you face will be harder.)
 * 1) The Dragonborn enters the city, with Ulfric Stormcloak, Galmar Stone-Fist and a group of Stormcloaks. Imperial soldiers will storm out of different places, to attack. Be careful not to dwell here for too long, as the Imperial soldiers simply respawn in groups, as killed.
 * 2) Move on into the city, break through the barricades and head left. More Imperials will spawn, here. Moving on, work through more barricades, until arriving at the door that General Tullius is found behind.
 * 3) Inside, head to General Tullius and Legate Rikke. Fight until Tullius surrenders to Ulfric and Galmar. After the conversation, Ulfric will ask if the Dragonborn would prefer to be the one to end Tullius' life. Optionally, the Dragonborn may elect to have Ulfric do the killing. Ulfric will give you his Sword of Devouring (in v1.9 a Daedric Sword of the Vampire), which absorbs enemy health when struck. The statistics of this weapon are entirely level dependent.
 * 4) Ulfric invites the Dragonborn to join him, while he addresses his people. Head outside, to find the Stormcloaks and Jarl Elisif gathered. Here, Ulfric will make his speech, to enthusiastic applause.

Transforming into werewolf form will also cause the Stormcloak soldiers to become hostile.

You can also use Odahviing as heavy firepower against the Imperials and the Stormcloaks will not be hostille towards him.

Trivia

 * It is hinted that Ulfric had some respect for Rikke as he tried to reason with her and gave her the opportunity to walk away, which she declined. It is also revealed in game that Rikke, Ulfric, and Galmar all served together in the Great War. As Rikke is a Nord, her heritage may have been another reason why Ulfric tried to talk her out of fighting him.
 * If the Blue Palace is entered during the battle, Bolgeir Bearclaw will have his weapon drawn and Elisif the Fair will be in her quarters, unable to be spoken to.

Gallery
Die Schlacht um Einsamkeit Битва при Солитьюде