From this date on Vila do Desterro and mainly the port began to have a strategic function because it was situated halfway between Rio de Janeiro and Buenos Aires, possibly two of the largest seaside cities of South America at that time. For this reason in 1739 the Capitania da Ilha de Santa Catarina was created and Desterro became its capital. Soon the most expressive seaside defensive ring of Southern Brazil started to be built: Santa Cruz, São José da Ponta Grossa, Santo Antonio and Nossa Senhora da Conceição da Barra do Sul fortresses.