Crux simplex

The term crux simplex was used by Justus Lipsius (1547–1606) to indicate a plain transom-less wooden stake used for executing either by affixing the victim to it or by impaling him with it (Simplex [...] voco, cum in uno simplicique ligno fit affixio, aut infixio). He thus distinguished two types of crux simplex: the crux simplex ad affixionem and the crux simplex ad infixionem.

Lipsius contrasted the crux simplex (both variations) with the two-timber structure that he called a crux compacta (Compacta Crux est, quae manu facta, idque e duplici ligno), and that he subdivided into three types: crux decussata (X-shaped), crux commissa (T-shaped) and crux immissa (†-shaped).

All these linguistic terms are of Lipsius's own invention and were not in use in ancient Roman times, however all of these forms of execution were used by the Romans, dating back to the Roman Republic.