This chapter traces the shifting fortunes of the Mascarenhas family in eighteenth-century Portugal through two case studies—the Counts of Sandomil and Alva—and the brief rise and fall of the Mascarenhas House of Aveiro. It highlights how wars, dynastic politics, and colonial appointments shaped noble trajectories, often producing short-lived titles undermined by financial strain, celibacy, or failure of succession. Pedro Mascarenhas’s military brilliance and troubled viceroyalty in India, Dom Luís Mascarenhas’s service in Brazil and Goa, and the Aveiro-Távora conspiracy illustrate how alliances, service, and missteps could elevate or destroy noble standing.