what did the emperor Blefuscu give Gulliver before his departure ? what convinced the ship's captain about Gulliver's story ?

"His majesty presented me with fifty purses of two hundred sprugs a-piece, together with his picture at full length, which I put immediately into one of my gloves, to keep it from being hurt."

Gulliver shows him what is in his pocket,

"whereupon I took my black cattle and sheep out of my pocket, which, after great astonishment, clearly convinced him of my veracity."