From this Protest the reformers received the name of Protestants, which they have since retained.
The emperor, flushed with success, now resolved, with new energy, to assail the principles of the Reformation.

Leaving Spain he went to Italy, and met the pope, Clement VII., at Bologna, in February, 1530.
The pope and the emperor held many long and private interviews.

What they said no one knows.

But Charles V., who was eminently a sagacious man, became convinced that the difficulty had become far too serious to be easily healed, that men of such power had embraced the Lutheran doctrines that it was expedient to change the tone of menace into one of respect and conciliation.

He accordingly issued a call for another diet to meet in April, 1530, at the city of Augsburg in Bavaria.
"I have convened," he wrote, "this assembly to consider the difference of opinion on the subject of religion.