Answer:
Irish convicts
Explanation:
European explorers were familiar with Australia since the 1600s. However, they stepped their foot on infertile and dessert parts of the continent, so they showed no interest for this new land. Upon finding fertile land in eastern parts of the continent, in the 1700s, James Cook claimed it a British land.
Britain has just lost its colonies in America, so they decided to send men to this new land. However, they considered it infertile, lacking in resources and hard to live on, so they sent convicts, in, what will be known as the First Fleet, in 1788.
Thus first contingent of ships carried around 1500 convicts, mostly Irish, with more than 100 000 convicts in the following years.
With them, Catholicism arrived in Australia, and later spread throughout the continent.
