The given chapter traces the most important passages in the history of urban conservation in Europe, focusing particularly on Italy. It begins by recalling the leading figures Camillo Sitte and Charles Buls, who were among the first to defend the ancient parts of cities from the extensive erasure of historic neighborhoods conducted for the sake of hygiene at the end of the nineteenth century. Thereafter, it elaborates on the theory of diradamento edilizio (“selective clearing”), which, opposing total demolition, was put forward by Gustavo Giovannoni to sanitize historic centers while preserving their character. With the aim of providing an overview of international debates on the historic city since the second half of the twentieth century, the main international documents are presented and scrutinized in terms of their innovative content. The chapter concludes with an outline of contemporary issues and challenges for the historic city today.