Timothy Matlack probably engrossed the parchment copy of the Declaration of Independence displayed at America250 events.
To engross a document means to prepare a carefully written official copy, usually in a formal hand. Congress ordered the parchment copy on July 19, 1776, after the Declaration had already been adopted and printed. Timothy Matlack, a congressional clerk, is generally credited with writing it.
This is not the same document as the first printed broadsides. John Dunlap printed roughly 200 broadsides soon after adoption, while the parchment copy was prepared for delegates to sign. Most delegates signed the engrossed copy on August 2, with additional signatures added later.
The wording “probably” matters because the surviving evidence does not provide an absolute modern signature from the scribe. John Dunlap was the printer of the early broadside, and Charles Thomson was Congress’s secretary; neither should be confused with Matlack’s role as the likely engrossing clerk.