During the Protestant Reformation of the sixteenth century, St. Nicholas was banished from most European countries.  Repalcing him were more secular figures, such as Britain's Father Christmas and France's Papa Noel.  The Dutch kept the St. Nicholas tradition alive.  As the "protector of sailors", St. Nicholas graced the prow of the first Dutch ship that arrived in America.  And the first church built in New York City was name after him.  In sixteenth-century Holland, children placed wooden shoes by the hearth the night of St. Nicholas's arrival.  The shoes were filled with straw, a meal for the saint's gift-laden donkey.  In return, Nicholas would insert a small treat into each clog.  In America, the limited-volume shoe was replaced with the expandable stocking, hung by the chimney with....expectations.  "Care" would not come until 1822.  The Dutch spelled St. Nicholass "Sint Nikolass", which in the New World became "Sinterklass".  Even the Dutch lost control of New Amsterdam to the English in the seventeenth century, Sinterklass was Anglicized to Santa Claus.
Much of modern-day Santa Claus lore, including the reindeer-drawn sleigh, originated in America, due to the popularity of a peom by a New York theology professor.  Dr. Clement Clarke Moore composed "The Night Before Christmas" in 1822, to read to his chidlren on Christmas Eve.  The poem might have remained privately in the Moore family if a friend had not mailed a copy of it (without authorial attribution) to a newspaper.  It was picked up by other papers, then it appeared in magazines, until eventually every line of the poem's imagery became part of the Santa legend.  It was in America that Santa put on weight.  The original St. Nicholas had been a tall, slender, elegant bishop, and that was the image perpetuated for centuries.  The rosy-cheeked, roly-poly Santa is credited to the influential nineteenth-century cartoonist Thomas Nast.  From 1863 until 1886, Nast created a series of Christmas drawings for Harper's Weekly.  These drawings, executed over twenty years, exhibit a gradual evolution in Santa--from the pudgy, diminutive, elf-like creature of Dr. Moore's immortal poem to the bearded, potbellied, life-size bell ringer familiar on street corners across America today.  Nast's cartoons also showed the world how Santa spent his entire year--constructing toys, checking on children's behavior, reading their requests for special gifts.  His images were incorporated into the Santa lore.
Rudolph, the Red-Nosed Reindeer: 1939, Chicago
"Rollo, the Red-Nosed Reindeer".  "Reginald, the Red-Nosed Reindeer".  Both names were considered for the most famoust reindeer of all.  And the now traditional Christmas song began as a poem, a free handout to department store shoppers.
In 1939, the Montgomery Ward department store in Chicago sought something novel for its Santa Calus to distribute to parents and children.  Robert May, an advertising copywriter for the store,
suggested an illustrated poem, printed in a booklet, that families would want to save and reread each holiday season.  May conceived the idea of a shiny-nosed reindeer, a Santa's helper.  And an artist friend, Denver Gillen, spent hours at a local zoo creating whimsical sketches of reindeer at rest and at play.
Montgomery Ward executives approved
name Rollo. Then Reginald. May considered
and finally settled on Rudolph, the prefe-
Rudolph became an annual television star,
Holland, Denmark, Sweden, Norway, Eng-
the countries whose own lore had enriched
haps most significantly, "Rudolph, the Red-
gists only new addition to the folklore of
the sketches and May's poem, but nixed the
other names to preserve the alliteration,
rence of his four-year-old daughter. 
and a familiar Christmas image in Germany,
land, Spain, Austria, and France--many of
the international St. Nicholas legend. Per-
Nose Reindeer", has been called by sociolo-
Santa Claus in the twentieth century.
(Source: Extraordinary Origins of Everyday Things by Charles Panati)