IMP XXXXII COS XVII P P (type I, B) (441 / 450)
Bust of Theodosius II facing, cuirassed, wearing a helmet with crest and a pearl diadem. Holding a spear passing behind his head with the right hand and a decorated shield with a horseman slaying an enemy, with the left hand.
Constantinople seated left on a throne, holding a spear with the left hand and a globe surmounted by a cross with the right hand. A shield behind the throne and a star in the field to the left.
Marks
Photo of a coin sold the 27/06/2018 by Classical Numismatic Group, Electronic Auction 423, lot 383, link to the sale: https://www.acsearch.info/search.html?id=5103314, link to their website: https://www.cngcoins.com/.
Another copy sharing the same obverse die, sold the 22/05/2021 by Leu Numismatik, Web Auction 16, lot 3800, link to the sale: https://www.acsearch.info/search.html?id=8103669.
Another copy with a rounder shield, sold the 28/09/2021 by Ira & Larry Goldberg Coins & Collectibles, Auction 123, lot 1382, link to the sale: https://www.acsearch.info/search.html?id=8563800, link to their website: https://goldbergcoins.com/.
Mark CONOB.
Type I: with mark CONOB or COMOB (CONOB here) and the reverse legend usually ending before the shield. No punctuation on legend on either side. A square throne, the right leg as a triangular protuberance, stiff drapery and vertical scepter. This corresponds to type III of RIC X. Var B is the same as RIC X: smaller and rounder shield.
See AYC #21, RIC 323: https://www.all-your-coins.com/en/archives-anciennes/romaines-imperiales/imp-xxxxii-cos-xvii-p-p-type-i-a-441-450, for the commentary explaining the entire coinage.