David, an eminent classical scholar, was born at Stolpen in Prussian Pomerania, in the year 1723. Of the early part of his studies little is known, but it appears that he was some time at Schlaff, from which he removed to Konigsburg, where he met with the celebrated Kant, whose system has so much engaged the attention of Europe. He afterwards went to Gottingen. Gottingen to attend the learned Gesner, and to enlarge his knowledge of the Greek language. Some time after this period he formed an acquaintance with Ritter and Berger while he resided at Wittoburg, where he continued about two years; and his first public attempt, being a thesis De Galia Placidia Augufta, daughter of Theodosius, and the sister of Arcadius and Honorius, was in this place. Rhunkenius was engaged to go to Leyden by Ernelli, to complete his knowledge of ancient literature. He gave up the study of divinity, for which he was at first disposed, and prevailed with his parents to allow him to go to Leyden, where he arrived with recommendations to many of the learned, and pursued his studies with avidity and zeal, accompanying Alberti in his visit to the Spa in the year 1750. Hemitterhuis wished to attach him to Holland, urging him to persevere in the study of the law, as affording an additional chance of employment. This advice he thought proper to follow, and published a translation of some works of Theodorus, Stephanus, and some other celebrated lawyers in the time of Justinian, which he found in manuscript in the university of Leyden.

He went to Paris in the year 1755, where Caperonier, who was at that time keeper of the king's library, kindly received him; and he formed an acquaintance with Dr S. Mulgrave and Mr T. Tyrwhit, who were there for the purpose of examining the manuscripts of Euripides. He had also formed the resolution of going to Spain, but Hemitterhuis recalled him, as he needed his assistance as lecturer in the Greek tongue. In 1755, Rhunkenius took possession of his office, and read an excellent discourse De Graecia Artium et Doctrinarum Inventrice.

About this time he was useful to Ernelli, in his edition of Callimachus; and in 1761, he succeeded Oudendorp as professor of history and of eloquence, delivering an oration De Doctore Umbratico. About a year after this event, Rhunkenius was offered the chair of Gesner by the university of Gottingen, which he declined accepting, but he recommended Heyne, who was the successful candidate.

In 1764 he married an Italian lady, who, about six years afterwards, lost both her speech and sight by a stroke of apoplexy. She had two daughters, one of whom was afterwards blind, and the wife of our author survived her husband. The desire of Rhunkenius to do Ernelli a favour, made him turn his attention to the Memorabilia of Xenophon; and he was led to examine with particular attention, the treatise of Longinus on the sublime. Having risen superior to his domestic misfortunes about the year 1772, he pursued his new edition of Velleius Paternus, and he prepared a second edition of Epistolae Criticae, and a collection of Scholia on Plato. In the year 1766, he published a valuable little tract De Vita et Scriptis Longini, in the form of a thesis, to which he prefixed the name of one of his pupils. His Velleius Paternus appeared in 1779, and in 1780 Homer's reputed hymn to Ceres. In 1786, he published the first part of Apuleius, which had been prepared by Oudendorp, and a new edition of his own Timaeus in 1789, and at the same time he collected and published the works of Marc-Anthony Murat, in 5 vols. 8vo.

Both the body and mind of Rhunkenius were much weakened in consequence of the loss of friends, an attack of the gout, and the misfortunes of the Batavian republic; but he was in some measure relieved by the satisfaction he felt at the dedication of Homer by Wolf, although he was not of that writer's opinion that the works of Homer were written by different authors. He sunk into a kind of stupor on the 14th of May, 1798, which in two days put an end to his existence.

His knowledge and learning were unquestionably great, and he was allowed to be lively, cheerful, and gay, even to an extreme. Many posthumous honours were conferred upon him, and a pension settled on his unfortunate widow. When Whyttenbach took possession of Rhunkenius's chair, he delivered a discourse on the early age of Rhunkenius, which he proposed as an example to the Batavian youth who made the belles lettres their study.