The history of public finances in Portugal from the middle nineteenth century to World War I is distinguished by the ambitious programme of public investment in infrastructure, negative financial consequences this elicited, culminating default. In this article we approach the Portuguese financial period with a relatively new methodology for evaluating sustainability, which emphasises the inter-temporal nature budgeting. The results obtained allow us to quantify the separated Portuguese finances from a sustainable path throughout period. Although the generational imbalance of Portuguese the time seems massive in the context of today's benchmarks, economic and financial impact should have been more limited, government's relatively low weight in the economy and demographic