Why was the election of 1800 decided in the House of Representatives?

The 12th Amendment required this process.
The 12th Amendment required this process.

No candidate received a majority in the Electoral College.
No candidate received a majority in the Electoral College.

Both candidates were from the same party.
Both candidates were from the same party.

No candidate wanted to be vice president.

Although it is not explicitly mentioned as a reason, the election of 1800 was indeed decided in the House of Representatives due to the fact that no candidate received a majority in the Electoral College. In this election, Thomas Jefferson and Aaron Burr received the same number of electoral votes, which led to a tie. According to the rules at the time, the House of Representatives would then hold a contingent election to choose the president from the top three candidates, with each state delegation having one vote. This resulted in a lengthy and contentious process, eventually ending with Jefferson being elected as the third President of the United States.