Complex sentence: Montet believed that his excavations at Tanis had uncovered Pi-Ramesses, however after his death Austrian Egyptologist Manfred Bietak discovered that although Montet had discovered Pi-Ramesses stonework at Tanis, the true location of the ancient city lay some 30km to the south.
Split into simpler sentences: Montet believed that his excavations at Tanis had uncovered Pi-Ramesses. After his death, Austrian Egyptologist Manfred Bietak discovered that although Montet had discovered Pi-Ramesses stonework at Tanis, the true location of the ancient city lay some 30 km to the south.