Why was Lincoln being advised to free the slaves? The North was losing the war and needed help from the slaves.
The blockade of Southern ports was ineffective.
This would prevent the recognition of the Confederacy by England. What did Lincoln's Emancipation Proclamation state?

This would prevent the recognition of the Confederacy by England. ... Lincoln's Emancipation Proclamation stated that slavery would officially end. It also brought the Thirteenth Amendment which brought significance to the war, for now people were fighting to free slaves.

so it’s the number 1 “ The north was losing the war and needed help from the slaves“.

This would prevent the recognition of the Confederacy by England.

Explanation:

President Abraham Lincoln issued the Emancipation Proclamation on January 1, 1863, as the nation approached its third year of bloody civil war. The proclamation declared "that all persons held as slaves" within the rebellious states "are, and henceforward shall be free."

the viking voyages took place during the middle ages, which was about this time. 500 to 1350. the viking voyages took place during the middle ages, which was about this time.