Comparative, transnational and global viewpoints have emerged as useful methodological approaches over the last decades. They have allowed historians to overcome national as well as other limited frameworks within which they used to work. In this sense, the Spanish and Portuguese empires provide an eye-catching opportunity to connect and interrelate spaces that had formerly been studied mostly as naturally separated blocks. This panel is an opportunity for scholars focusing on the XV-XIX Centuries to present their works and to discuss possible research agendas. Even if preference will be given to works on the two empires as a whole object, this does not imply, of course, the exclusion of presentations focusing on only one of them. The two issues that will structure this panel are: circulations-representations and governance. People, things and knowledge circulated within a vast Atlantic space. What were the means and conditions that allowed these movements? Which were the global representations –historically or spatially speaking such as medieval, enlightened, etc. - that contributed to configure local/global perceptions about life and reality in both empires? These two issues will be articulated around the concept of government, although without limiting it only to matters of legislation or political institutions. In practice, government is linked to circulations (of knowledge, merchandises, functionaries and migrants) and representations (about the social structure, the power of others, the success or failure of reforms). Researchers are very welcome to present their works and to discuss about the connections between these two empires which have frequently been studied as separate nationals units.