how was gulliver taken to the city gate

Gulliver was tied down to a kind of stretcher. He was drugged and carried to the city gates,

"I lay in a profound sleep, by the force of that soporiferous medicine infused into my liquor. Fifteen hundred of the emperor's largest horses, each about four inches and a half high, were employed to draw me towards the metropolis, which, as I said, was half a mile distant."