Boetius à Bolswert (also Boetius Adamsz Bolswert, Bodius; c. 1585, – late 1633) was a renowned copper-plate engraving engraver of Friesland origin. In his time the paintings of Peter Paul Rubens called forth new endeavours by engravers to imitate or reproduce the breadth, density of mass and dynamic illumination of those works. Boetius Bolswert was an important figure in this movement, not least because he was the elder brother and instructor of the engraver Schelte à Bolswert, whose reproductions of Rubens's landscapes were most highly esteemed in their own right.
The birthplace of the Bolswerts at the little town of Bolsward, Friesland, was confirmed by Cornelis de Bie in his Het Gulden Cabinet. Boetius came early in life to Holland, where he appears around 1610; he was then dwelling in Amsterdam, and sometimes also in Utrecht.
In 1610 he produced his four scenes of the Horrors of the Spanish War, after designs by David Vinckboons. Reproductions of large landscapes by Vinckboons and Gillis van Coninxloo III were among his early successes, employing a dense and diffuse technique, in a genre to which he later made transforming contributions. In 1615 and 1616 he was licensed by the Dutch States-General to engrave from the portraits of Michiel Jansz van Mierevelt, such as the portraits of Elizabeth and Frederik of Bohemia. In 1618 he depicted the ceremonial funeral-bed of the newly deceased Philipp Wilhelm, Prince of Orange.
However Bolswert's most notable collaboration in this period was with Abraham Bloemaert, after whom he produced various series. It is thought they worked closely, for Bolswert carefully imitated aspects of his graphic style, and has been described as his pupil. His 1611 series Pastorals using Bloemaert models shows the early fruits of that influence. Their collaboration in various works from 1612 on the theme of Saints and Hermits culminated in 1619 in Antwerp in the Sylva Anachoretica Ægypti Et Palæstinæ (The Hermit Woodland of Egypt and Palestine), a quarto (230mm) volume depicting imaginary portraits of 25 male and 25 female hermits of antiquity, with facing descriptive Latin texts, printed by Hendrick Aertssens. Dutch and French editions were reprinted in the same year. This was apparently commissioned by the Jesuit Heribert van Rosweijde (1569–1629), (founder of the project for the Acta Sanctorum taken up by the Bollandists), rector of the Jesuit college at Antwerp. Rosweyde dedicated the Bolswert work to his benefactor, Abbot Antoine de Wynghe of Liessies Abbey, Département Nord, France. It was evidently a companion-book to Rosweyde's major Latin work Lives of the Fathers (biographies of early Church hermits) of 1615, a compilation from which was produced at Antwerp in 1619 by Jan van Gorcum.