Guillaume Brouscon

Guillaume Brouscon was a Breton cartographer of the Dieppe school in the 16th century. He was from the port of Le Conquet, near Brest, which is shown prominently in large red lettering on his 1543 map of the world.

He published his Brouscon's Almanachs in 1546, which were used for their information on tides by English, French and Breton sailors. They allowed to known the direction of tidal currents, and to calculate tide level depending on the phase of the moon.