Complex sentence: The number of the troops in the province is difficult to estimate, there are documents to show 10,200 soldiers in the fortresses in 1546, and 12,451 soldiers in 1568.
Split into simpler sentences: The number of the troops in the province at this time is difficult to estimate. There are documents to show 10,200 soldiers in the fortresses in 1546, and 12,451 soldiers in 1568.