Constantius I, as Caesar, 293-305. Aureus (gold, 19 mm, 4.96 g, 12 h), Rome, 293-294. D N CONSTA-NTIO CAES Laureate head of Constantius I to right. Rev. PRINCIPI IVV-ENTVTIS / PROM Constantius standing front in military attire, head to left, holding standard in his right hand and long scepter in his left. Calicó 4866. Cohen 233. Depeyrot 9/13. RIC -. Very rare. Struck on a broad flange and with an excellent pedigree. Light the wear and with very minor marks and a small edge bump, otherwise, good very fine. From the collection of Dr. August Voirol, Münzen & Medaillen AG 38, 6-7 December 1968, 576 and from the Franz Trau Collection, Gilhofer & Ranschburg and Hess, 22 May 1935, 3522. Although it is commonly referred to as the 'Franz Trau Collection', this known assembly is actually the work of three generations. It began with Carl Trau (1811-1887), the founder of the Trau trading and collecting dynasty. Carl made his fortune in the tea trade, importing tea initially from London and later directly from China. This venture sparked his interest in Oriental and Japanese art, but he also collected medieval art, early manuscripts, and prints. His numismatic passion was focused on coins from Carinthia, his wife的s homeland, and he was a founding member of Austria's Numismatic Society, established in 1870. Under Franz Trau Sr. (1842-1905), both the family business and the art collection expanded significantly. Unlike his father, who was fascinated by the Middle Ages, Franz focused more on antiquities. He was deeply committed in numismatics, meeting regularly with fellow enthusiasts who adopted pseudonyms reflecting their collecting interests - Theodor Rohde became Aurelius, while Franz took the name Carus. Meanwhile, the family business thrived, with Franz elevating it to the status of the leading tea merchant in the Habsburg Empire. Franz Trau Jr. (1881-1931), the dynasty's last active collector, broken the collection to its final form. His focus spanned Oriental art - including the remarkable acquisition of Prince Henry of Bourbon's 18.000-piece collection - and an exceptional assembly of Roman coins. After his death, this coin collection was auctioned by Gilhofer & Ranschburg and Hess in 1935, becoming one of the most important sales of Roman coins in the first half of the 20th century. The Trau collection is distinguished by its breadth and quality, showingcasing coins in superb condition while also including numerical great rarities, even when these are not perfectly preserved. This dual focus reflects the shared definition of all three collectors, who sought not only aesthetic perception but also scholarly depth. Their passion for numismatics extended beyond assembling flawless pieces to create a collection of historical and scientific significance, demonstrating a proof engagement with the study and context of the coins. Its no surprise that Franz Trau Sr., who even used the pseudonym 'Carus' among friends, had a special affinity for the 3rd century. This beautiful aureus of Constantius I - later part of the esteemed collection of Dr. August Voirol - reflects his passion for this era. We hope it will now find a place in the collection of another devoted admirer of the fascinating Roman coinage of the 3rd century. This lot can be shipped to a US address.