Arthur is a tall, handsome, and accomplished young man, if somewhat "dandified." In high society, he can serve as an acceptable escort for the young ladies of New York's elite Four Hundred. Yet his love for Louise leads him unhesitatingly into a happy marriage.
Arthur is the son of an American railroad magnate and a Sicilian mother. The elder Weldon was abducted by brigands while traveling on the island in his youth, and escaped with the aid of the head brigand's daughter. The pair married and settled in the United States; but the elder Weldon came to neglect his wife as he devoted himself more and more to business. In time his Sicilian bride abandoned her husband and returned home, leaving her three-year-old son behind.
As the boy Arthur approached maturity, he developed differences with his father, who threatened to disown the youth. In this period, Arthur fell in love with Louise Merrick; but his questionable financial situation kept him from winning the approval of Louise's ambitious mother. Arthur followed Louise to Europe on her trip abroad, and used his background to masquerade as an Italian aristocrat. (Aunt Jane's Nieces Abroad)
His father's abrupt death made Arthur a wealthy young man; and he earned the grudging respect and acceptance of John Merrick, Louise's uncle. The romance between Arthur and Louise had its rough spots, but eventually the two married; their wedding was a major social event. (Aunt Jane's Nieces in Society)
When the Merrick cousins start a newspaper at their summer home in Millville, they list Arthur as Editor in Chief, though he actually has almost nothing to do with the paper. This leads to his involvement in a comic duel. (Aunt Jane's Nieces on Vacation)