In this paper I address some elements in Piero Sraffa's thinking that are connected to his conceptualization of the phases of capitalism. Sraffa describes various stages of capitalism using similar categories to the ones employed in the model of the economy provided in Production of Commodities. This is done by distinguishing the role of population, land and (circulating, intermediate and fixed) capital in each stage. Sraffa changed his conceptualization of fixed capital over the years, until he reached its final formulation. The conceptualizations of fixed capital that Sraffa discusses, together with his remarks on money which are made through an analogy with circulating and fixed capital, provide some elements that shed light on Sraffa's view of the dynamics of capitalism.