Conversation so far:
What was this during?
During the War of 1812, the British captured the fort in the Siege of Fort Mackinac.
What did this do for him?
The victorious British attempted to protect their prize by building Fort George on the high ground behind Fort Mackinac.
Why was this so terrible?
In 1814, the Americans and British fought a second battle on the north side of the island.
What did this mean to him?
The American second-in-command, Major Andrew Holmes, was killed and the Americans failed to recapture the island.

Question: What did he try and do?
Self-contained rewrite: What did Major Andrew Holmes try and do