This maybe 'way off base', but the European looking head has the look of a death mask. Investigating the early history of the the Europeans entering Ceylon, I found this...
".......On 21 August 1630, the Portuguese began the march to return to Colombo but were attacked by the Kandyan army at Vellavaya. Most of the Lascarins betrayed the Portuguese – only 500 remained loyal – and joined the enemy. For the Kandyans this was an overwhelming victory: of the Portuguese expedition, only 130 men survived and surrendered. The captain General Dom Constantino de Sá y Noronha was captured and beheaded. His head was carried by Prince Mahastana (later crowned Rajasimha IIEmperor of Ceylon) and presented to the Emperor Senerat......"
Could the 'head' be a symbolic reminder of this event...I wonder
I have not been able to find an image of General Dom Constantino de Sá y Noronha to help / disprove this theory.
Regards David