Complex sentence: The Spanish occupied Santa Marta in May 1812 (until 1818) and there and at Cartagena minted coins that were neither of uniform weight nor of uniform fineness (making them relatively easy to counterfeit).
Split into simpler sentences: The Spanish occupied Santa Marta in May 1812 (until 1818). Both in Santa Marta and Cartagena the spanish minted coins that were neither of uniform weight nor of uniform fineness (making them relatively easy to counterfeit).