This is first presidential election in which two candidates were presented by opposing parties. John Adams ran as a Federalist, while Thomas Jefferson ran as a Democratic-Republican.
Adams, winning the most electoral votes, became president. However, his running mate, Thomas Pinckney, would not be elected vice president. As the Constitution laid out, the person with the second most electoral votes would become vice president. That man was Thomas Jefferson. So, the election of the 1796 put two opposing parties into the White House. The 12th Amendment changed the electoral process.