Jews always knew and debated the borders of Eretz-Yisrael. The different borders.
They had to because there were religious requirements involved.
And they were the sole people who consistently throughout history had a firm geographical and topographical concept of what there homeland was. It was in their minds, their language, their texts, their religious/cultural ceremonies.
And the other people residing in the country, the Arabs who arrived as a conquering force in 638 CE and occupied the country?
Seems they had a bit of a problem.
From this article by Zachary J Foster: "Was Jerusalem Part of Palestine? The Forgotten City of Ramla, 900–1900", British Journal of Middle Eastern Studies, 43(4)(2016): 575-589:
I guess geography wasn't their strong point.