Petrus Bertius (1565 – 1629) was a Flemish theologian, historian, geographer and cartographer who was born in Beveren, Flanders in November 1565. A religious refugee, Bertius eventually settled in Amsterdam because of the city’s liberal religious policies. After finishing his studies, he was appointed a professor of mathematics and a librarian at the University of Leiden.

Bertius was well-known for his input into the miniature pocket atlases first produced by Cornelius Claesz in 1600. These popular atlases, with maps engraved by Pieter van den Keere and Latin text composed by Bertius, were frequently re-issued and enlarged over the years.

His recognition among geographers was established by his text in the pocket atlas Tabularum Geographicarum which was first published in 1600 in Amsterdam. In general, Bertius’ beautiful miniatures are usually valued more highly than those of Ortelius and are also relatively scarce.

Bertius Inlet in Antarctica is named after Bertius who published an early separate map in 1616 of Terra Australis Incognita. In 1618 Bertius became cosmographer and historiographer to Louis XIII of France, and moved to Paris, where he died in October 1629.