To find and profile the earliest journalists one would probably need some German or Dutch. In the English world, the earliest such were renowned writers such as Daniel Defoe, Henry Fielding, Jonathan Swift, Samuel Johnson, Joseph Addison and Richard Steele. Fielding and Defoe were the earliest novelists, Addison and Steele essayists, Swift the great satirist, Johnson the father of the dictionary.
Whatever journalism has become, as it has adapted to a series of media and constantly changing conditions, the progenitors laid out certain ground rules by their example: that journalists had a love of words, a deep curiosity, can tell a story and select the best format to do it in, go places that other professions wouldn't dream of. Statesmen like Benjamin Franklin did a stint in journalism, documenting the times even as he made history himself; an inventor hurrying it along as it were.
Multi-skilling is necessary if you are to write convincingly about banking or people, for instance. The reader presumes upon the writer to display a rural background, agricultural experience, or working on the land in some capacity before publishing a progressive farming article. Either that or interview those involved in a keen take that will interest readers and make sure you represent the views of those quoted accurately and compile them in a meaningful way.