This paper documents an analysis of English demographic change over the period 1573–1873. A simultaneous equations model is developed in order to test four alternative demographic theories—the constant equilibrium wage theory, the constant fertility theory, Lee's original (1973) synthesis theory, and a new, composite theory. Each is a special case of a general demographic model which provides both for exogenous technological change and for endogenous migration behavior. Two-stage least-squares estimation yields parameter estimates and test statistics, which provide evidence of the superiority of the composite theory of demographic change. By statistically affirming the composite theory of demographic change, this paper confirms that the mortality level played a dominant role in English demographic change during the preindustrial period. The analysis also provides support, however, for the classical notion that shifts in the labor demand function were a dominant cause of long-run population changes, subsequent to the beginning of British industrialization.