At its height, Aksum ruled most of present-day Eritrea, and parts of Ethiopia, Yemen, Saudi Arabia, Djibouti, and Sudan. After converting to Christianity about 330 B.C., the cross replaced the disc and crescent on coins. Due to climate change and trade isolation, Aksum began to decline in the 7th century when the last coins were issued. Aksum is now a country village in northern Ethiopia. One of the most curious aspects of Axumite coinage is the use of gilding on some of the silver and bronze coins. The amount of gold used would not be enough to significantly change the value of the coin, and the reason for this labor-intensive process remains somewhat a mystery. According to regional tradition, the Ark of the Covenant is housed in the Church of Mary of Zion at Aksum. The Ark, according to legends, was brought to Aksum by King Solomon and the Queen of Sheba's son and placed under guard. No one but the one guard priest is allowed in, thus no one can verify the Ark's existence.