Before reaching Ierisssos, one of the harbours to start the trip to Athos, there are some long stretched beaches. The straight line of the beach is interrupted by a more curved piece of land.
On older maps this piece of land is also to been seen. The 18th century map on the right is a hand drawn with text in French. The land is called Pointe du Monaster. 
On the map by Ortelius from 1585 it seems that this piece of land used to be an island called Caprus Insula . Also the map of 1650 by Laurenberg below mentions the island. For a moment I believed that the piece of land on the modern maps was once the island of Caprus. Did the coastline changed f.i. by making dams or was it a natural process? No, the good answer is: the old maps are not that accurate.
Thanks to our Dutch follower Hans Overduin I know now that the Caprus Insula is far more located to the north of Mount Athos as you can see on the map below.
Caprus / Kavkanas / Kapros island.
If you like looking at the old maps from Mount Athos or Greece (or the world) in general check this out. You wil not be dissapointed: The complete 18th century Atlas from Ottens made in Amsterdam, the Netherlands. This volume contains the countries Italy and Greece. 
hv
For the history of Caprus / Kavkanas / Kapros, see http://www.my-favourite-planet.de/english/europe/greece/macedonia/stageira/olympiada-photos-002.html . I’m afraid the island didn’t disappear at all, which by the way doesn’t make it less interesting.
Dank je Hans, aardig dat je het nog interesting vind maar je hebt gelijk. Ik denk dat mijn Hollandse geest te snel uitgaat van land dat even buit gemaakt wordt op de zee. Ik ga er een draai aan geven.