The term "tying the knot" comes from India!
The phrase 'tying the knot' derives from a longstanding Hindu wedding tradition in India. Instead of a wedding ring, a Hindu groom will give his bride a "mangala sutra" or "mangalsutra", also referred to as a Thaali—a sacred thread of love and goodwill made of black and gold beads. He will loop the thread around his bride’s neck, tying the cord in three knots to symbolize the unity of their two souls for 100 years. The act of tying the knots concludes the ceremony, officiating the couple’s marriage. Much like a wedding ring, once a Hindu woman has wed, she will always wear her mangala sutra, as it signifies to others that she is married.