The first paper studies the role played by increases in children’s quality in triggering fertility declines using provincial level data in early 20th century Spain. Evidence supports the existence of a negative association between changes in children’s education and parents’ fertility. Exploiting alternative instrumental variable strategies that use indirect and direct measures of local support to education expansion, we suggest that this negative relationship can be given a causal interpretation. This provides evidence in favour of theories that argue that increases in children’s quality are crucial in explaining fertility declines. The second paper studies the role of historical institutions in promoting education across Spanish districts in the late 19th century. We explore this issue focusing on a specific historical characteristic: the ownership structure. Evidence suggests that lower concentration in ownership is positively related to literacy and local support to education. We address potential bias of OLS estimates by employing an instrumental variable strategy that uses exogenous variation in geographical characteristics.