Onde primeira feira? The hebrew/arabic way of naming the days of the week in Portugal It is astonishing that "Monday" is segunda-feira (the second market day) just like in Arabic (yawm al-ithnayn, meaning "second market day" as well). Counting market days is common and done in the same way in both languages. This way of counting and naming days is obviously a very clear heritage of Arabs in Portugal. Neither Romans nor other Roman languages in Portugal's neighborhood count days that way. Strangely enough Monday still used to be second market day, hinting at the fact, that under muslim and jewish rule Sunday used to be considered the first market day of the week and not the holy Day of the Lord ("Domingo" in Portuguese and Spanish) of the Christian church!