Prussia. Friedrich I, AD 1701-1713. AV, Ducat. 3.61 g. 23.02 mm. Obv: FRIDERICUS REX. Right-facing, armored, and laureated bust of Frederick I, draped in a ceremonial court mantle. Positioned immediately beneath the truncation of the bust is the signature C G, representing the initials of the Mintmaster Caspar Geelhaar. Rev: MONETA AUREA REGNI PRUSS 1702. The crowned royal coat of arms of Prussia, enclosed within an ornate decorative cartouche flanked and embellished with palm branches. Ref: Fb. 2309; Olding 110 a. Very Fine. The year 1702, marking the minting of this specific issue, closely follows the historic event of January 18, 1701, when Frederick III, Elector of Brandenburg, crowned himself in Königsberg and proclaimed his elevation as Frederick I, King of Prussia. Given that this kingdom was established within Prussian territories situated outside the formal jurisdiction of the Holy Roman Empire, the reverse legend REGNI PRUSS (Of the Kingdom of Prussia) functions as an official manifesto of this newly acquired status and independent sovereignty, permanently inscribed in gold for the diplomatic audience of European courts and major commercial emporiums. In standard numismatic literature—specifically within the authoritative corpora of von Schrötter and Olding—this particular issue is classified under the prestigious rubric of 'of great rarity' (von großer Seltenheit). These gold pieces were never intended for general currency circulation or daily commercial transactions; instead, they were struck in highly restricted quantities (low emission volume) to serve as diplomatic presentation pieces, royal gratuities, or prestige payments reserved exclusively for the court elite. Due to centuries of geopolitical conflicts, systemic meltings, and collateral losses, only a nominal number of specimens in a high state of preservation have survived to the present day. Consequently, this ducat stands as one of the most elusive Prussian gold coins in existence, heavily sought after by institutional museums and premier private collections worldwide. From Brandenburg Electorate to Prussian Kingdom