Later, the island became part of the commercial empires of Pisa, Genoa, and the Spanish, and was annexed in 1718 by the dukes of Savoy.
The island got annexed. 
mnli hypothesis: The island got annexed.  premise: Later, the island became part of the commercial empires of Pisa, Genoa, and the Spanish, and was annexed in 1718 by the dukes of Savoy.