The First Edition of Bertius's Caert-Thresoor.
The Caert-Thresoor, a groundbreaking pocket atlas first introduced in 1598 and later re-envisioned by Petrus Bertius in 1600, marked a pivotal shift in the nature and design of minor atlases. This 1600 edition, co-published by Cornelis Claesz and Jan Jansz. of Arnhem, deviates from its earlier iterations by presenting Bertius' comprehensive geographical treatise, for which the maps act as visual supplements. In prior editions, the text was far less important, serving merely as an explanation of the maps. In this first Latin edition of 1600, the order of the maps mostly follows that in the editions of 1598 and 1599. Starting in the second edition, the maps were reorganized to align more harmoniously with the classical order found in Ptolemy's Geographia.
At the beginning of the 17th century, Amsterdam's emergence as a cartographic powerhouse was in full swing. The initial Caert-Thresoor atlas established an unprecedented standard for smaller atlases, as noted by Peter van der Krogt and Günter Schilder. Eminent scholars, including Bertius and Jacobus Viverius, methodically revised the text. The compact, yet excellently engraved maps, demonstrate clarity, elegance, and design prowess. These maps didn't merely serve the atlas but found utility in various foundational geographical and travel publications from Amsterdam during that period. Their content mirrors Amsterdam's state-of-the-art cartographic capabilities, benefiting from the latest updates on newly charted territories.
Another distinguishing feature of this atlas lies in its deviation from the Antwerp-produced pocket atlases, which largely remained simplified renditions of Ortelius's Theatrum Orbis Terrarum. Instead, the Caert-Thresoor embarks on an innovative trajectory, assimilating fresh material accrued in Amsterdam during the 1590s. Infused with both Portuguese insights and Dutch exploratory data, these additions are particularly evident in the atlas's second (and following) books, focusing on non-European territories. Notably, this section showcases in-depth maps of regions such as the Philippines and the East Indies archipelago, tracing back to the cartographic work of Jan Huygen van Linschoten in 1595.
This is the first edition of what Peter van der Krogt (IIIa, page 409) terms "the second category of the Caert-Thresoor, in that it has text by Petrus Bertius and not the initial anonymous author:
The second category of the Caert-Thresoor has a text by Petrus Bertius. It was published again by Cornelis Claesz. along with Jan Jansz. of Arnhem (father of Johannes Janssonius of Amsterdam) as co-publisher. The text by Bertius is entirely different from the text by the "unknown" original author. Bertius wrote a new geographical treatise on the whole world, for which the maps serve as illustrations. This is contrary to the first editions of 1598 and 1599, where the text explained the maps. At the end, Bertius refers to Ptolemy's Geographia, comparing his chapters with the books of Ptolemy.
In the first edition (1600), the order of the maps is nearly the same as in the editions of 1598 and 1599. Starting with the second edition, the order was completely changed to fit in with the classical order of maps in Ptolemy's Geographia.
What makes the Caert-Thresoor Special
The pocket atlases published in Amsterdam from 1598 "set a new standard for minor atlases" (Van Der Krogt, IIIa, 373):
The Caert-Thresoor of 1598 set a new standard for minor atlases. Scholars like Petrus Bertius and Jacobus Viverius edited the text. The small maps are extremely well engraved; they are neat and clear and elegantly composed. They served many purposes in other books published in Amsterdam. Their contents reflect the level of cartography in Amsterdam at the turn of the century, where up-to-date information on newly discovered regions was readily available. The Caert-Thresoor is a collection of maps to which the text was adapted and not the other way around as is the case with many geographical studies. Its success must have that prompted Jodocus Hondius to publish a reduced edition of Mercator's Atlas in 1607.
Schilder, MCN VII, page 460:
The pocket atlases that were produced in Antwerp remained to a large extent simplified smaller-scale versions of Ortelius's Theatrum Orbis Terrarum. Meanwhile, the Caert-Thresoor broke away from this folio atlas and conformed less strictly to the structure and layout of that atlas. Production of the Caert-Thresoor moved in a new direction by including much new material that had been collected in the 1590s in Amsterdam. This material was based partly on Portuguese information and knowledge, partly on that derived from Dutch voyages for trade or discovery. The revisions showed up mainly in the second book, which should be seen as a kind of up-to-date supplement. This part covers the non-European countries. Here one finds, among other things, detailed maps of the Philippines and the archipelago of the East Indies. The maps were taken directly from the map that Jan Huygen van Linschoten made in 1595.
Petrus Bertius was a Flemish historian, theologian, geographer, and cartographer. Known in Dutch as Peter de Bert, Bertius was born in Beveren. His father was a Protestant preacher and his family fled to London around 1568. The young Bertius only returned to the Low Countries in 1577, to attend the University of Leiden. A bright pupil, Bertius worked as a tutor and was named subregent of the Leiden Statencollege in 1593. He ascended to the position of regent in 1606, upon the death of the former regent, who was also Bertius’ father-in-law. However, due to his radical religious views, he eventually lost his teaching position and was forbidden from offering private lessons.
His brothers-in-law were Jodocus Hondius and Pieter van den Keere, who were both prominent cartographers. Bertius began his own cartographic publishing in 1600 when he released a Latin edition of Barent Langenes’ miniature atlas Caert Thresoor (1598). He published another miniature atlas that first appeared in 1616.
By 1618, Bertius was named cosmographer to Louis XIII. He converted to Catholicism and took up a position as professor of rhetoric at the Collège de Boncourt (University of Paris). In 1622, Louis XIII created a chart of mathematics specifically for Bertius and named him his royal historian. He died in Paris in 1629.