Province House in Charlottetown is where the idea of Canada was born. In 1864 the leading citizens of Britain's the maritime colonies were encouraged to meet to discuss the future. The Americans were sniffing around looking for territory, Great Britain was more interested in India but did not want to lose influence in North America and encouraged the small, separate colonies to discuss some kind of common cause.
When Upper and Lower Canada heard of this meeting they crashed the party, hoping to solve their own problems and changed the discussion to one of larger scope, and the notion of Confederation was born. The results of the Charlottetown meeting were taken back to their respective colonies, reportedly after much partying and they agreed to meet in Quebec the next year to strike a deal and have another party.
The Prince Edward Island representatives at Quebec, perhaps feeling a bit under the weather and not getting an satisfactory answer to the vexing question of the absentee landlords plaguing the Island colony did not sign on. It was not until 1873 that PEI actually joined the Confederation, "Long Courted, Won at Last!"