Where does “esforzar” come from?

esforzar (Spanish) comes from Old Portuguese esforçar, from Vulgar Latin exfortiare, from Latin fortis, from Old Latin forctis, from Proto-Italic forktis, from Proto-Indo-European bʰerǵʰ- — to rise; high, lofty; hill, mountain.

esforzar (Spanish): encourage; strain; strive