Short answers, pulled from the story.
The Gospel of Matthew describes three men entering a house to see a child with Mary his mother and kneeling down to pay him homage. They open treasure chests to offer gold, frankincense, and myrrh before leaving for their own country by another path after receiving a dream warning them not to return to Herod.
Crowns do not appear until the 10th century in most Western works. By that time the dress had lost any Oriental flavor in many cases compared to earlier examples from the 4th century showing Persian trousers and Phrygian caps.
Gaspar Melchior and Balthasar became the prevailing names for the three kings over the centuries representing Europe Asia and Africa respectively. Balthasar is very commonly cast as a young African or Moor while Old Caspar receives Oriental features and Melchior represents Europe and middle age.
Hugo van der Goes created the Monforte Altarpiece featuring this theme while Jan Gossaert painted his version between 1510 and 1515 for London's National Gallery. Hieronymus Bosch also treated the subject with his distinctive style and Gerard David produced a work circa 1515 now held in London.
Eastern Orthodox Church commemorates the event on December 25 instead of January 6. Western Christianity marks the Feast of Epiphany on January 6 each year reflecting distinct theological traditions across Christian branches.