One of the first actions of Posadas was to create a naval fleet from scratch, which was to be financed by Juan Larrea, and appointed William Brown as lieutenant colonel and chief commander of it, on March 1, 1814. Against all the odds, on 14 May 1814 the improvised patriot navy engaged the Spanish fleet and defeated it three days later. This action secured the port of Buenos Aires and allowed the fall of Montevideo, which could not stand the siege any more, on 20 June 1814.