What was the Virginia dynasty?

The Virginia dynasty were four of the first five presidents, all from Virginia:

George Washington (served 1789-97)
Thomas Jefferson (served 1801-09)
James Madison (served 1809-17)
James Monroe (served 1817-25)

John Adams of Massachusetts (served 1797-1801) was the only one of the first five presidents not from Virginia.

His son John Quincy Adams broke the hold of the Virginia dynasty by taking office as president 1825-29.