Looking for Matias of Vila Real IN Portugal

My grand father was born in Vila Real, Portugal, on year of 1898.
When he was about 16 years old, he went to Brazil.
First he arrived at Recife, Pernambuco State, Brazil.
After, he moved to São Paulo, São Paulo State, Brazil.
My father told me my grand father has changed his name when arrive in Brazil.
We suppose his name was João Matias Junior. He changed to João Martins Junior.
He had some relatives living in Mogi das Cruzes, São Paulo State, Brazil.

Someone can help me to find my ancient family ?

Thanks,

Celso Martins