Cornelis Anthonisz. (often spelled "Anthonisz.") Theunissen was a distinguished Dutch painter, engraver, and mapmaker born in Amsterdam in 1499 and active in the early 16th century. He is renowned for his contributions to cartography and cityscape representations, most notably his panoramic maps of Amsterdam.

Anthonisz. came from an artistic family—he was the nephew of Jacob Cornelisz. van Oostsanen, a prominent artist of the time, from whom he likely learned the basics of painting and printmaking. His detailed woodcut map of Amsterdam from 1538, commissioned by the city government, is considered one of his most significant works.

This map, titled Bird's Eye View of Amsterdam, is one of the earliest known representations of the city and reflects the growing urban development and bustling activity of Amsterdam in the early Renaissance period. The level of detail in his map shows not only a keen sense of artistic ability but also an advanced understanding of geography and spatial arrangement, which were remarkable for the time.

Beyond his maps, Cornelis Anthonisz. was also involved in various painting projects, including portraits and religious scenes, although his cartographic work remains his most lasting legacy. His influence extended to subsequent generations of Dutch mapmakers, as his works served as important references for later maps of Amsterdam and other regions in the Netherlands. Anthonisz. passed away around 1553, but his contributions to Dutch cartography and the cityscape genre continue to be celebrated in the history of art and cartography in the Netherlands.