Complex sentence: However, the mosque slowly fell into disuse, and crumbled to ruins over the centuries, likely due to the fact it pushed the construction techniques of the time to the very limit, and the fact it was built too quickly.
Split into simpler sentences: However, the mosque slowly fell into disuse, and crumbled to ruins over the centuries. It was also likely due to the fact it pushed the construction techniques of the time to the very limit, and the fact it was built too quickly.