Cape of Needles
Discovery of the Coincidence of Magnetic and True North
Rounding the southern coast of Africa in the 1480s and 1490s, Portuguese navigators discovered one point where magnetic north and true north were virtually identical. They called this place the "Cape of the Needles" (Cabo das Agulhas) because all compass needles pointed to true north.
On this 1516 map, Cape Agulhas is clearly marked with the compass needle pointing due north.
As you can see from the map, Portuguese sailors knew this so well that they had it on all their maps!