And you know that exactly from what?
So many were slain at Marnas Pell, on both sides, that the Veil is said to be permanently sundered, the ruins still plagued by restless corpses. But each year, the Chantry pushed further and further into the Qunari lines, although local converts to the Qun proved difficult to return to Andraste's teachings. By the end of the Storm Age, the Qunari were truly pushed back.
Thus the Armada was formed. The pirates brought their knowledge of stealth and trickery to bear, plaguing Qunari supply lines and even launching seaborne invasions against the Qunari coast
The Felicisima Armada takes Estwatch following a massive naval battle with the Qunari
The period when the Qunari controlled Kirkwall was at least brief. four years after the occupation, Orlesian forces entered the city and took it back.
(last two from WoT)