How "Tuesday" become "Mangalvar"?
In the Rama Katha Rasa Vahini, Swami explains how Mangalwar came into being.
When Ravana is vanquished, Rama sends Hanuman to break the good news to Mother Sita. She is so happy, and says, “I don't know what gift to give you Hanuman. You have brought such wonderful news for me.”
Hanuman says, “Mother, you are so happy. What other happiness do I need in all the three worlds?”
Then Mother Sita says, “Hanuman, I don't know what I can give you but I grant you this boon: Since you have brought me such great news on this day, from this day onwards, let this day of the week be known as Mangalvar – the auspicious day.”