This isn't definitive by any means but comes from mone source:
The Electoral College
Excerpt from an original document located at Jackson County, MO Election Board
http://www.uselectionatlas.org/INFORMATION/INFORMATION/electcollege_history.php
In order to appreciate the reasons for the Electoral College, it is essential to understand its historical context and the problem that the Founding Fathers were trying to solve. They faced the difficult question of how to elect a president in a nation that:
• was composed of thirteen large and small States jealous of their own rights and powers and suspicious of any central national government
•
contained only 4,000,000 people spread up and down a thousand miles of Atlantic seaboard barely connected by transportation or communication (so that national campaigns were impractical even if they had been thought desirable)
• believed, under the influence of such British political thinkers as Henry St. John Bolingbroke, that political parties were mischievous if not downright evil, and
• felt that gentlemen should not campaign for public office (The saying was "The office should seek the man, the man should not seek the office.").
(snip)
The function of the College of Electors in choosing the president can be likened to that in the Roman Catholic Church of the College of Cardinals selecting the Pope.
The original idea was for the most knowledgeable and informed individuals from each State to select the president based solely on merit and without regard to State of origin or political party.