Some sporting rivalries endure regardless of ladder positions and other circumstances of the day.

Clearly the connection between the West Coast Eagles and Fremantle will ensure the RAC Derby forever evokes strong emotions and competitiveness with the Dockers. For geographical reasons these clashes will always be relevant.

The Eagles and Sydney Swans are almost as far removed from each other as is possible in the AFL landscape but they, too, have an unbreakable connection.

Not just because of the extraordinary sequence of close matches in the mid-2000s when six matches between the two clubs were decided by a total of 13 points. Extraordinarily four of those games were finals, two of them Grand Finals.

As probably should have been the case, the two clubs shared the glory in the ultimate games with Sydney winning in 2005 and West Coast prevailing 12 months later.

But there is another significant reason for the inexorable link; a connection that was created decades before the Eagles were even formed.

And on Saturday it will take centre stage for the match between the two clubs at the SCG.

Since 2010 the Eagles and Swans have competed for the HMAS Sydney II Trophy, recognising Sydney as the home port and Western Australia as the final tragic resting place of a vessel that has a special place in Australian maritime history.

Celebrated for her successful battles in the Mediterranean, where she famously sank the Italian cruiser Bartolomeo Colleoni, HMAS Sydney (II) and her crew of predominantly young men received a hero’s welcome on her return to Australia in February 1941. She was then tasked with escorting troopships to South-East Asia, following an Indian Ocean route along the west coast of Western Australia.

It was on the return of one of these voyages that she encountered the Kormoran on November 19, 1941 off the WA coast near Shark Bay. The Kormoran was disguised as a Dutch merchant vessel and used the element of surprise to sink HMAS Sydney II, with all 645 crew perishing.

The Kormoran was also sunk but 318 of its 390 personnel survived.

The HMAS Sydney II Trophy was donated to the West Coast Eagles and Sydney Swans by the Finding Sydney Foundation and is now the centrepiece of matches between the clubs since 2010.

The trophy displays Sydney's distinct badge, campaigns and battle honours in polished bronze on a jarrah base and backboard. 

The player judged best afield is also awarded the perpetual Gun Shell Trophy as well as a pure silver 2008 HMAS Sydney commemorative coin, crafted by the Perth Mint.