This large Antiochus III Seleucid bronze, called "Denomination A" in SC (Houghton & Lorber) appears to be very rare and the best example of this type (SC 1060). The M control mark is unlisted/unknown until now for this coin and the reverse monogram is associated with a longtime Antioch magistrate who was transferred to Asia Minor c. 203 BC [S.C. Part 1 Vol 1] .
Antiochos III Megas (“Antiochos the Great”), was a Seleukid King, born in the period c. 243 - 241 BC, he reigned 223 - 187 BC, and killed in 187 BC leading a raid on a temple treasury in Elymais. He expanded the Seleucid territories and positioned himself as a champion of Asian independance from Rome. A story of diplomatic encounter between a Roman ambassador and Antiochus ends with Antiochus explaining:
"I am a relative of Ptolemy," he said, "and I shall be his father-in-law, although I am not so now, and I will see to it that he renders gratitude to you. I am at a loss to know by what right you meddle with the affairs of Asia when I never interfere with those of Italy." And so they separated without coming to any understanding, and both sides broke into more open threats.
-Appian, Syrian Wars 1.3
In the later years of his reign (circa Dec 190 - Jan 189 BC) Antiochus III lost a decisive battle against Rome who was allied with Eumenes II: the battle of Magnesia which led to a treaty at Apamea, which pushed the Antiochus' control East of the Tuarus mountains.
Thanks to David K., developer/owner of Seleucid resource site AllCoinage, I have a better identification of this coin as SC 1060, resolving clearly the question of mint as Antioch. The mint assignment is supported by SC 1054 which has the same M in the known controls. The M in outer left was not seen before because known examples were too poorly preserved or off struck to show the M on the lower left. Ω/P is referenced in SC Online for this coin (Houghton monogram 607.20).
Seleukid Kingdom, Antiochos III, 223-187 BC, AE, Antioch mint Size: 26.5mm, 11.90g Obv: Laureate head of Apollo right Rev: BAΣIΛEΩ[Σ] ANTIOXOY, Tripod; Ω/P monogram above M to left
Ref:Seleucid Coins (part 1) 1060
This coin is a "Denomination B" which is also a rare coin, especially in this condition. It has a youthful portrait of Antiochos III. I find only 1 sold by CNG in 2005 in ACSearch.
Seleukid Kings of Syria, Antiochos III 'the Great', 223-187 BC, Æ 20mm (8.13 g, 1h), Ekbatana mint
Obv: Diademed head of Antiochus III right
Rev: Nike standing left; anchor to inner left, monograms to outer left [and right]
Ref: SC 1240; SNG Spaer -; Houghton 1162
This next coin is a "Denomination A" the largest of the Seleukid AE coins from this period. The obverse reminiscent of a large Roman bronze with the prominent ship's prow. Although I've photographed the reverse horizontally to make it easier to read, in Seleucid Coins the authors write that although the die axis suggests that the type was intended to be horizontal, "certain symbols read correctly when the trident is vertical". This coin weighs in at the high end of the media range for this type and slightly below the middle of the diameter range which is reported as 21-26mm. The minting of this largest denomination was suspended after 2 years.
Seleukid Kings of Syria, Antiochos VII, 138-129 BC, Æ 23mm (11.14g), Antioch mint, year 175 (138/7 BC)
Obv: Prow of galley right; caps of the Dioskouroi above
Rev: Upright trident; monogram in outer left field, cornucopiae in inner left field; date across lower field EΟΡ (right end of photo above)
Ref: SC 2064.10