DE LUCA, GIOVANNI BATTISTA. – Jurist, born in Venosa in 1614, died in Rome on 5 February 1683. He studied law at Salerno and Naples, where he obtained his degree at the age of 21, and practised as an advocate for many years until he moved to Rome in 1645. Having entered the ecclesiastical state, he became auditor and secretary of memorials; on 1 September 1681 he was created cardinal by Innocent XI.
His principal work is the Theatrum veritatis et institue, sive decisivi discursus per materiae seu titulos distincti, etc., in 21 volumes, including the supplements (Rome 1669–73 and Venice 1734): a kind of repertory containing, arranged by subject, the forensic pleadings and speeches delivered by him in the practice of advocacy. At the end of each book there is an appended doctrinal exposition.
A shortened version of this work in Italian was subsequently produced by D. L. himself, under the title Il dottor volgare ovvero il compendio di tutta la legge civile, canonica, feudale e municipale nelle cose più ricevute nella pratica, etc., in 15 vols. (Rome 1673). His Discorso dello stile legale is also famous; in it he advocates, among other things, the use of the Italian language in judicial proceedings.
D. L. is the most representative figure of the practical jurisprudence of the seventeenth century. He begins by assigning due importance to the customs and particular laws of peoples in relation to the common law, affirming that the authority of civil laws arises from the consent and usage of peoples. He also criticizes the bad practice of assigning authority to legal doctrines on the basis of the arithmetical number of their adherents, maintaining that one must consider not the number, but the quality of the jurists and that of their foundations and arguments.
The Instituta civilia must also be attributed to him, an institutional work modelled on Justinian’s, published posthumously under the care of Crescimbeni and, like the Dottor volgare, containing cross-references to the more extensive work of the Theatrum.
D. L. reveals an open mind and a brilliant spirit, at times not untouched by caustic irony, as well as a broad and modern outlook on legal problems. His works are distinguished by their extensive knowledge of canon law; moreover, the application of civil law itself is treated in that spirit of canonical equity which had its particular efficacy and natural setting in the tribunals of the Papal States, especially that of the Roman Rota.