Complex sentence: An earlier, 1608 map of Gibraltar by Cristóbal de Rojas includes the Flat Bastion and the South Bastion, although England claimed that Spain had never finished the construction of the Flat Bastion.
Split into simpler sentences: An earlier, 1608 map of Gibraltar by Cristóbal de Rojas includes the Flat Bastion and the South Bastion. However, England claimed that Spain had never finished the construction of the Flat Bastion.