first article
Noun
Meaning
(civil law) A prototype or archetype.
(innovation, manufacturing) A preproduction model, initial sample or pilot model.
Source: en.wiktionary.orgExamples
Nonviolence is the first article of my faith. It is also the last article of my creed.
The first article carrying Vonnegut's byline, 'This Business of Whistle Purchasing,' a lighthearted criticism of a school fund-raiser, was submitted at the urging of his sophomore English teacher.
[The first article about NSA surveillance] "It's everywhere," Snowden said, clearly excited. "I watched all your interviews. Everyone seemed to get it."