Complex sentence: Jauja in the fertile Mantaro Valley was established as Peru's provisional capital in April 1534, but it was too far up in the mountains and far from the sea to serve as the Spanish capital of Peru.
Split into simpler sentences: Jauja in the fertile Mantaro Valley was established as Peru's provisional capital in April 1534. But it was too far up in the mountains and far from the sea to serve as the Spanish capital of Peru.