The Magi are known under different names such as "Three Wise Men", "Kings from the east", "wise men from the east, and "The Three Kings". As mentioned above, their original "occupation" was not royalty at all, but class of priests who were adept at astrology. Their sightings of the Star of Bethlehem would have completed the prophecy announcing the birth of an important person, of which they were all aware. History has a way of tweaking the facts. Around the 3rd century, the Magi began to be viewed as kings. (Note: They did not become popularly known as kings until the 10th century when painters portrayed them as such.) Different names have been given to the Magi. Hormizdah, Yazdegerd and Perozdh have been noted in one account (Persian). Hor, Basanater, and Karsudan named in yet another (Ethiopian). By the time the 6th century rolled around these men were given the names of Bithisarea, Melichior and Gathaspa. As time went on the Western church settled on Balthasar, Melchior and Caspar/Gaspar.
There is a famous mosaic in Sant'Apollinare Nuovo in Ravenna dating from AD 550 (yes – “Sant”). In this mosaic Balthasar is middle aged with a black beard, Gaspar is old and has a white beard and Melchior is young and beardless (Take a close look a your nativity set and you will see how these descriptions have modified ever so slightly over time.) In the 9th century the Magi were depicted to represent the 3 races. Balthasar was African, Gaspar a white European, and Melchior was Asian or variously Arabian.
Most nativity sets show Melchior, an older man with grey hair and long beard, giving Jesus the gift of gold. Gaspar, young and beardless (alternately short beard without grey), gives the gift of frankincense, and Balthasar, middle-aged with a typical beard, gives the gift of myrrh. As not all nativity makers check the same sources variations exist.
Interesting things of note that are consistent among the common knowledge:
--Marco Polo claimed to have seen the three tombs of the Magi, Saveh, south of Tehran in the 1270's. In Persia is the city of Saba, from which the Three Magi are traditionally considered to have set out from. In this city they are buried (see next note), in three very large and beautiful monuments, side by side. And above them there is a square building, beautifully kept. The bodies are still entire, with hair and beard remaining.
Source: POLO, Marco, The Book of the Million, book i.
--According to tradition, the remains of the Magi are at the Shrine of the Three Kings at Cologne Cathedral. It is believed that St. Helena discovered their remains on her pilgrimage to Palestine and the Holy Lands.