Is it possible that Amalia came into usage during the time that Queen Amalia was the queen consort of Greece in the 19th century? Although this royal family was not Greek and not always popular she does seem to have left her mark:
"When she arrived in Greece as a Queen consort in 1837 she had an immediate impact on social life and fashion. She realized that her attire ought to emulate that of her new people, and so she created a romantic folksy court dress, which became a national Greek costume still known as the Amalia dress.
It follows the Biedermeier style, with a kaftan (καβαδι) top over which is worn a richly embroidered jacket. It was completed with a cap or fez, traditionally worn by married women, or with the kalpaki (a toque) of the unmarried woman, to which was added the black veil for going to church.
This dress became the usual attire of all Christian townswomen in both Ottoman Empire-occupied and liberated Balkan lands as far north as Belgrade.
In the early years of the new monarchy, Queen Amalia, with her beauty and vivaciousness brought a spirit of smart fashion and progress to the impoverished country. She laboured actively towards social improvement and the creation of gardens in Athens, and at first won the hearts of the Greeks with her refreshing beauty. The city of Amalias and the village of Amaliapolis were named for the Queen."