From the history of press releases

[Ivy] Lee‘s policy of press relations also can be seen in his use of the handout, or press release as we call it today. Lee made more extensive use of the handout than anyone before him, and frequently suffered the wrath of the press for doing so. But Lee made the press release respectable. His handouts were always clearly marked to indicate who wrote them, and on whose behalf. Before, handouts had been “planted” without naming the source, or information was leaked by anonymous tips.

James E. Grunig and Todd Hunt, Managing Public Relations, 1984, p. 33