A case could be made that there are even older Protestant groups than the Hussites. Hus was inspired by English theologian and reformer John Wycliffe, Olson writes. (Photo: Randy OHC / Wikimedia Commons)
This year - 2017 - many Protestant Christians around the world will be celebrating what they think is the 500th anniversary of the birth of Protestantism.
Many consider Oct. 31 as "Reformation Day" and celebrate it as the annual anniversary of the birth of Protestantism because it was on that day in 1517 that Martin Luther nailed his "95 Theses" to the cathedral church door in Wittenberg, Saxony.
Well, any historian worth her salt knows that's a somewhat arbitrary choice for the birth of Protestantism.
One could just as well date it to the day of Luther's "Tower Experience" or his excommunication from the Roman Catholic Church or any number of other days.
In fact, in Switzerland many Protestants think it was not Luther but Ulrich Zwingli, the reformer of Zurich, who launched the Protestant Reformation.
I sit in an office on a Protestant Christian campus where, not far away, one can worship in about 20 to 25 Protestant congregations whose roots bypass Luther and Zwingli.
These are the Czech Brethren churches of central Texas. Contrary to what many observers wrongly assume, they are not Moravians.
The latter are an offshoot of the Czech or Bohemian Brethren, also known as the Unitas Fratrum (Unity of the Brethren) founded by Prague preacher and theologian Jan Hus, who taught and preached the same things as Luther a century earlier.
Hus was perhaps the first real Protestant, and the Czech Brethren stem directly from his reforming work in Bohemia. They have every right to claim to be the oldest Protestant churches in the world.
In fact, during his lifetime, Luther was often called "the Saxon Hus" by his enemies. Hus was burned at the stake at the Council of Constance in 1415 after being promised safety to and from the council by the emperor.
But, a case could also be made that there are even older Protestant groups than the Hussites. Hus was himself inspired by English theologian and reformer John Wycliffe, who died in 1384.
Wycliffe, however, unlike Hus, left behind no organized religious group that survived. Some historians think, however, that Wycliffe's followers, known as the Lollards, did survive even if they eventually merged into other non-conformist groups in England.
Perhaps the best claim to be "the first Protestant group" is laid by Italy's Waldensian churches, which have spread to some other parts of the world (including South America).
Peter Waldo (1140-1205) and his followers believed and taught many of the same Protestant doctrines as Hus and Luther, including "sola scriptura" (Scripture alone), "sola fides" (faith alone) and the priesthood of all believers.
One of the disillusioning things about studying history is discovering that what you thought you knew isn't necessarily so.
This year we will celebrate the birth of the Reformation, but some of us will celebrate it with a degree of skepticism about its correctness.
Roger Olson is the Foy Valentine professor of Christian theology and ethics at George W. Truett Theological Seminary in Waco, Texas. He is the author of numerous books, including "Counterfeit Christianity" and "The Story of Christian Theology." This article is edited from a version that first appeared on his blog. It is used with permission.