The Adoration of the Magi
The Magi were a priestly caste of ancient Persian Zoroastrianism and were revered by classic authors as wise men. It was their alleged power over demons gave rise to the word "magic." Magi comes from Middle English magi, from Latin magì, pl. of magus (meaning sorcerer), from Greek magos, from Old Persian maguš.
In Christian culture, the Magi were men who came, bearing gifts of gold, frankincense, and myrrh, to adore the newborn Jesus. They were guided by the Star of Bethlehem. Their number was not identified in the Gospel of Matthew, but Christian tradition has set their number as three, called them kings, and named them Caspar or Gaspar, Melchior, and Balthazar. The Feast of Epiphany, January 6th, commemorates their visit.
Their coming was foretold. "The kings of Tarshish and the Isles shall offer gifts, the kings of Arabia and Seba shall bring tribute. All kings shall pay Him homage, all nations shall serve Him" (72:10-11). Isaiah also prophesied the gifts: "Caravans of camels shall fill you, dromedaries from Midian and Ephah; all from Sheba shall come bearing gold and frankincense, and proclaiming the praises of the Lord" (Isaiah 60:6).
The Western tradition of the names of the Magi derive from an early 6th Century Greek manuscript, translated into the Latin Excerpta Latina Barbari The description seems to be of a mosaic of the magi, possibly those at Ravenna. A pseudo-Bedan text, Collectanea or Excerpta et Collectanea apparently continues the tradition of three kings. The text is said to be from the 8th or 9th century, of Irish origin, and first found in a printed edition of works ascribed (probably incorrectly) to St. Bede the Venerable at Basel in 1563.
One source states that the pseudo-Bedan text gives us the following clues about these men.
The oldest of the Magi was Melchoir, King of Arabia. He had a long gray beard and gave gold as a gift, symbolizing the acceptance of Christ as King.
Balthazar, King of Ethiopia, was middle-aged, swarthy, bearded, and bore the gift of frankincense, symbolizing Christ as High Priest.
Finally, Caspar was King of Tarsus, in his twenties. His gift was myrrh, which was used in making medicines. This symbolized Christ as the healer and great physician.
It is said that after discovering and honoring the Savior, the Magi returned home and surrendered their high positions, gave their property to the poor, and went to spread the Gospel. The apostle St. Thomas is said to have baptized them forty years later in India, ordaining them as priests. An excerpt from a Medieval saints calendar printed in Cologne reads: "Having undergone many trials and fatigues for the Gospel, the three wise men met at Sewa (Sebaste in Armenia) in 54 (AD) to celebrate the feast of Christmas. Thereupon, after the celebration of Mass, they died: St. Melchior on 1st of January, aged 116; St. Balthasar on 6th of January, aged 112; and St. Gaspar on 11th of January, aged 109." They became martyrs and were buried in the walls of Jerusalem. 
The Empress St. Helena (circa 248-330, mother of Constantine I) supposedly discovered their bodies in Persia in 325 AD during her pilgrimage to the Holy Land and brought them to Constantinople, where their remains rested in the Mosque of St. Sophia. It was she who established their identity within the early church although the Magi were not referred to as saints until the twelfth century. St. Helena died in 330.
Shortly thereafter, Eustorgio I, ninth bishop of Milan, received the remains of the Magi inside a huge Roman marble sarcophagus from the Emperor Constantine I (circa 288-337), and brought them to Milan on a wooden cart pulled by a team of oxen. The cart entered the city through Porta Ticinese, and then sank into the mud. Eustorgio decided that this was a sign from God, and built the first basilica on that site.
In 1163 or 1164, the Holy Roman Emperor Friedrich I (called "Barbarossa" meaning "Redbeard," 1122-1190) presented Cologne (Koln), Germany with a gift which he had taken from Milan after he had captured the city in March, 1162 -- the bones of the Three Wise Men. It is said that the remains were transported in three ships.
Within a few years, a shrine to house the relics was begun. The workshop of the goldsmith Nikolaus von Verdun was occupied for 50 years in the crafting of a golden shrine to house the relics (1180-1230). The shrine containing the relics can be seen today directly behind the high altar in the Cathedral. Fervent pilgrims began to flock to Cologne, which quickly became one of the primary religious sites in Germany.
A fabulous shrine was seen to need a stupendous church to house it, and the city of Cologne set about rebuilding its cathedral on a grand scale. Construction was begun in 1248 by the Archbishop Konrad von Hochstaden, in order to provide a more fitting cathedral to house the relics of the Three Magi. By 1265, the first of the chapels along the back of the cathedral were completed and in 1322, the Inner Choir with the High Altar was consecrated (even though this section had been completed around 1300). After 1322, the pace of construction slowed considerably, eventually grinding to a halt in 1560 due to a lack of funds. It was not until 1842 that construction was resumed by the King of Prussia, Friedrich Wilhelm IV. It took another 32 years of work to finish the Cathedral, with the last stonework being placed upon the South Tower in 1880.
After taking 632 years to complete (1248-1880), the Cathedral Church of SS. Peter and Mary in Cologne is the largest Gothic structure in northern Europe. It is currently the most visited building in Germany -- with 15,000,000 people a year come to view its beauty and its treasures. The shrine of the Three Wise Men is so famous that the church itself has become popularly known as the Dreikoenigenkirche (the Church of the Three Kings).
In 1906, some of the bones were returned to Milan and are now kept in an urn just above the altar of the Magi.
The cathedral was severely damaged by Allied bombing during WWII. The restoration was finished in 1956. However, the golden shrine which contained the relics was not damaged.