Because it was when America was separating from the British to make america its own country.
Formal should be the answer. It seems most appropriate.
Answer:
Francisco Coronado was born in Salamanca, Spain in 1510 and came to Mexico in 1535. He was a Spanish conqueror, or conquistador who visited New Mexico and other parts of what are now the southwestern United States and hoped to conquer the seven cities of gold. In 1540 he was sent to find these cities but discovered them to be only poor Indian pueblos in what is now New Mexico. In 1541 Coronado went to look for "Quivira," a land said to be rich in gold. He reached what is now eastern Kansas, but found only Indian villages. Fransisco's expeditions failed to produce gold. Coronado and his men returned to Mexico in 1542. Some of his men discovered the Grand Canyon of the Colorado.
Explanation:
Here's what I found
C encyclopedia article by franklin roosevelt
This is false, it was part of the compromise of 1850