Las Siete Partidas — a thirteenth-century Castilian code still cited in 1820 Louisiana

The law book compiled at the court of Alfonso X from 23 June 1256, which Castile never let go: pushed to last place in the order of authorities in 1348 and kept there for five centuries, taught as derecho patrio in the universities, carried to the Indies as the residual law behind every American code, and translated into English at the expense of the state of Louisiana in 1820 because its courts still had to apply it — slave law and all.