What is a Protestant:
A Protestant is one who follows Protestantism, the form of Christianity created during the Reformation of the sixteenth century and spread across Europe and later the world.
Origin of Protestant:
In 1517 the theologian Martin Luther began a split from the established, Latin, church by speaking out on the subject of indulgences. As the Pope decided how best to deal with Luther, the theologian and his colleagues effectively evolved a new form of the Christian religion which was taken up by many princes and towns of the German empire. Debate ensued, with the Pope, Emperor and Catholic governments on one side and members of the new church on the other.
In 1526 a meeting of the Reichstag, in practice a form of German imperial parliament, issued the Recess of 27 August stating that each individual government within the empire could decide which religion they wished to follow. However, a new Reichstag which met in 1529 was not so amenable to the Lutherans and the Emperor cancelled the Recess. In response, the followers of the new church issued the 'Protest', which protested against the cancellation on April 19th.
Despite differences in their theology, Southern German cities aligned with Swiss reformer Zwingli joined other German powers following Luther to sign on to the ‘Protest’ as one. They thus became known as Protestants, those who protested.