"PROTESTANTS" AND "ROMAN CATHOLICS"?

"Protestants" and "Roman Catholics", two terms in popular usage today, have been with us since the  sixteenth and seventeenth centuries.  What exactly are their origins? 

Martin Luther

In 1529, princes sympathetic to Martin Luther at the Imperial Diet at Speyer, issued a "protest" against the German Emperor, Charles V and his Catholic allies. From this point on, Luther's adherents were called "Protestants". Eventually, the label was applied to all who adhered to the tenets of the Reformation. 

King James I

King James I of England died in 1625. Towards the end of his reign, he sought to arrange a Spanish Catholic marriage for his son Charles.  It was during the negotiations, in 1623, that Catholics in England first became known officially as "Roman Catholics".  This was at the insistence of the Spanish who were sensitive to the fact that the Church of England regarded itself as the "Catholic Church in England".

You might like to delve deeper but, briefly, that is it.