Answer:
The Treaty of Guadalupe Hidalgo
explanation
The Treaty of Guadalupe Hidalgo, that brought an official end to the Mexican-American War (1846-1848), was signed on February 2, 1848, at Guadalupe Hidalgo, a city north of the capital where the Mexican government had fled with the advance of U.S. forces.
Answer:
It Depends.
Explanation:
Notable leaders include Adolf Hitler and Kaiser Wilhem. Current leader is Angela Merkel
Thomas Jefferson. Now I just have to make this "at least 20 characters to explain it well". I'm not entirely sure how to explain Thomas Jefferson more though.