The Battle of Dagobah was one of the last conflicts of the Tricolus Terror Campaign. It was the only victory the Galactic Empire achieved during the Campaign. Ackbar said of the disaster, "Had the Empire wanted to, they could strike back hard at us and put us to rout."
Admiral Ackbar, hoping to drive home their successes, ordered an attack on Dagobah, where a small regiment of Imperials were supposedly garrisoned. It turned out to be the 900th Legion and 14th Battle Group led by a Grand Admiral. The Rebels arrived, but were slaughtered because of the faulty information. Within three hours, the Republic had fallen back, leaving 4,000 of their 10,000 man army behind.
This success was not carried out. The Imperial Grand Admiral in charge was killed days later when Order 44 was executed. Any chance to change the fortunes of the campaign was gone.