Editors' note. This paper traces the two-thousand-year history of conditional sentence types from Latin to the modern Romance languages. The rich documentation of these languages allows detailed consideration of the thoroughgoing changes in the tense/aspect/ mood systems of the verb. In spite of successive shifts and new formations, the system of conditionals remains fundamentally the same in terms of basic semantic parameters of hypotheticality (real, potential, unreal) and time (past, nonpast). However, the boundary between potential and unreal conditionals is less clear-cut than between real and either of them, and the time parameter is less clear-cut in potential and unreal than in real conditions. This paper relates to those of König, Bowerman and Reilly in its dynamic approach, and to ter Meulen's and Reilly's in its focus on temporality.