Complex sentence: During this époque, the King's troops, infantry and cavalry, was composed in half of foreigners, and foreign formation had to wait for Louvois, to see numbers diminish notably in proportions.
Split into simpler sentences: During this époque, the King's troops, which formed the infantry and cavalry corps, were composed in half of foreigners. Foreign formation had to wait for Louvois, to see numbers diminish notably in proportions.