In 1864 Brazil invaded and occupied Uruguay.  Paraguayan leader Francisco Lopez planned to attack southern Brazil and reach Uruguay by going through Argentina; instead he met with hostility on the part of Argentina, who would not let Lopez pass through.  
In 1864 Brazil invaded and occupied Uruguay.  Paraguayan leader Francisco Lopez planned to attack southern Brazil and reach Uruguay by going through Argentina; instead he met with hostility on the part of Argentina, who would not let Lopez pass through.  In January 1865, Lopez crossed the Argentine border, and an all-out conflict ensued.  FTP, name this war, in which Uruguay and Brazil teamed up with Argentina to defeat Lopez and his troops.
In 1864 Brazil invaded and occupied Uruguay.  Paraguayan leader Francisco Lopez planned to attack southern Brazil and reach Uruguay by going through Argentina; instead he met with hostility on the part of Argentina, who would not let Lopez pass through.  
War of the Triple Alliance