Mud Shows
At its most rudimentary level, Circus is defined as physical feats of daring, juxtaposed against the burlesque of a clown. The first time such a presentation was made in the United States is believed to be August 27, 1785, when Thomas Pool added to his exhibition of "equestrian feats of horsemanship," a clown to entertain the audience between acts. Shortly thereafter, John Bill Ricketts popularized the form with some help from the patronage of president George Washington. Thus, the nascent country began its love affair with the emerging art form. The two would continue to mirror each other as they each matured and flourished over the next century.
In the early 19th century, Isaac Van Amburgh and others popularized the travelling menagerie in the United States. Van Amburg himself was a menagerie attendant (or "cage boy") turned lion tamer. He presented his act, which included not only lions, but also tigers, leopards, panthers, and hyenas as living illustrations of the Holy Bible. As the wild beasts shied away in deference, Van Amburg became a living representation of Genesis 1:26--
And [God] said: Let us make man to our image and likeness: and let him have dominion over the fishes of the sea, and the fowls of the air, and the beasts, and the whole earth, and every creeping creature that moveth upon the earth.
These types of productions were the so-called "mud shows." Horse-drawn wagons were necessary to convey the performers and their charges to the next town; usually not more than ten or fifteen miles away. Early circus wagons had to be as light as possible, and had large, spindly wheels in order to successfully traverse the crude roads of early America.