RELIEVE: twenty years immersed in the chronology of Open Access.

Coinciding with the first 20 years of RELIEVE, this article presents a comparative analysis of the historical milestones of the journal and the worldwide Open Access movement, in order to better frame its evolution. We review some of the principal contributions made in the field of scientific communication during these two decades: the appearance and development of electronic journals, the development of the Open Access movement, the appearance of repositories, the development of platforms to manage articles, new databases, etc