Egyptian sculpture and other art was very rigid in presentation. Isis was most often shown topless because among other things she was a fertility goddess. The most significant thing about representations of Isis was her head dress. She was depicted wearing the moon on her head surrounded by two horn-like things. In her hand she carried the "ankh", a symbol which you may have seen. The ankh was an elongated circle with two arms stretching out on either side and and a long vertical projection coming from the bottom of the circle - it was a symbol of divinity and eternity and was carried by many of the gods and the Pharaohs and their queens. When the Egyptian empire was at it's peak, Isis became very closely associated with the Queens of Egypt. They referred to themselves as 'daughters of Isis'. Cleopatra VII was the last Queen to use this title.