ABSTRACT
This chapter analyzes the social and political effects of dynastic marriages between the Portuguese and Castilian-Aragonese crowns on the configuration of transnational, aristocratic families during the sixteenth and seventeenth centuries. It discusses the miscegenation of Iberian nobilities derived from dynastic marriages. The chapter articulates the structural characteristics of this group and its political impact with the individual trajectories and historical contexts in which they developed. The marriage of João de Alarcão with Margarida Soares de Melo represents the beginning of a transnational family trajectory between families from Castile and Portugal structured in the shadow of the royal court. João de Alarcão was the only son of the second marriage of Martín de Alarcón with Elvira de Mendoza. Fernão Martins de Mascarenhas reinforced the family links with the Mascarenhases and inherited part of the estates of Fernão Martins de Mascarenhas and his wife, thereby increasing his house's economic strength.
