The surname Vasallo is not as uncommon as you think. I'm a Filipino. In the Philippines, there are Vasallo's all over the place. But our origin is probably not related to any original Spanish Vasallo's. The Philippines was a colony of Spain for more than 300 years and every Filipino was forced to changed their surname to a Spanish sounding one so my ancestor chose Vasallo to be his name. Just thought you all like to know!