proptereā ... quod

Meaning

1. because, since
   Horum omnium fortissimi sunt Belgae, propterea quod a cultu atque humanitate provinciae longissime absunt [...]Of all these, the Belgae are the bravest, because they are furthest from the civilization and refinement of [our] Province …c. 52 BCE, Julius Caesar, Commentarii de bello Gallico 1.1
   Id silentio noctis conati non magna iactura suorum sese effecturos sperabant, propterea quod neque longe ab oppido castra Vercingetorigis aberant, et palus, quae perpetua intercedebat, Romanos ad insequendum tardabat.They hoped that, by attempting it at the dead of night, they would effect it without any great loss of men, because the camp of Vercingetorix was not far distant from the town, and the extensive marsh which intervened, was likely to retard the Romans in the pursuit.c. 52 BCE, Julius Caesar, Commentarii de bello Gallico 7.26

Origins

From proptereā (“therefore”) + quod (“because”).