آرتاشس یکم یا آرتاکسیاس یکم (به ارمنی Արտաշես Առաջին Բարեպաշտ، به لاتین Artaxes or Artashes) با جلوس بر تخت سلطنت ارمنستان سلسله پادشاهی جدیدی را بنیان گذاشت که مقدر بود از تاریخ ۱۹۰ تا سال یکم پیش از میلاد بر ارمنستان بزرگ سلطنت کند، سلسلهای که در دوران حکومت او ارمنستان به اوج قدرت خود رسید.
آرتاشس یکم موفق شد تعرضهای لشکریان سلوکیان برای دست یابی به ارمنستان را با موفقیت دفع کند، و از آنجا که سیاستمداری زیرک و مال اندیشی بود آنچه از دستش برمیآمد برای تضعیف قدرت آنان انجام داد. وقتی تیمارک حاکم ماد علیه سلوکیها سر بر شورش برداشت آرتاشس سپاهی به یاری او فرستاد و کمکش کرد تا او نیز بدل به سلطانی مستقل شود.
آرتاشس یکم با آلبانیای قفقاز نیز جنگید آنان را تا به ساحل چپ رود کورا پس راند و در آن سمت بر وسعت خاک ارمنستان افزود. چون در آن جنگها پسر پادشاه آلبانها به اسارت درآمده بود پادشاه مغلوب دختر خود ساتنیک را فرستاد تا آزادی برادرش را از آرتاشس بخواهد و از او تقاضای صلح کند، آرتاشس عاشق آن دختر شد و با وی ازدواج کرد.
Artaxias I (from Greek: Άρταξίας; in Armenian: Արտաշես Artašēs; Old Iranian: Artaxšaθra) was the founder of the Artaxiad dynasty of Armenia, ruling from 189 BC to 160 BC. He was succeeded by his son Artavasdes I.
Artaxias is the Greek form of the Armenian Artašēs, itself from the Old Iranian name *Artaxšaθra- (𐎠𐎼𐎫𐎧𐏁𐏂𐎠), equivalent to Greek Artaxérxēs (Αρταξέρξης). The name means "whose rule is through truth".
According to the Greek geographer Strabo, Artaxias and Zariadres were Macedonian generals of the Seleucid king Antiochus III the Great (r. 222 – 187 BC). He adds that after Antiochus III's defeat by the Romans in 188 BC, the two generals established themselves a kingdom in Greater Armenia. However, this statement has been dismissed by the recent discovery of boundary stones with Aramaic engravings in Armenia, which mentions Artaxias' proclamation of being "the son of Zareh (Zariadres)" and an "Eruandid (Orontid) king".
The ending of -akān in the engravings, originally used in Old Persian, was extensively used in the Parthian ostraca from Nisa and in later Armenian texts. Anahit Perikhanian thus confirms that both Artaxias and Zariadres, "far from being Macedonians, belonged in fact to the earlier native dynasty, albeit probably to collateral branches, and that the Eruandids, or Artaxiad/Artašēsids as they came to be known, with their Iranian antecedents, continued to rule Armenia as before." In the same manner of that of the monarchs of Pontus and Cappadocia, the Artaxiads stuck mainly to the royal traditions used by the former Achaemenid Empire. At the same time Greek influence was starting to advance in the country.
Artaxias and Zariadres united their armies to expand their dominions; the kingdom of Artaxias, originally centered around the middle of the Araxes river, expanded into Iberian land, and especially the territory of Media Atropatene, which lost its territories at the Caspian Sea and the districts of Syunik and Vaspurakan. Meanwhile, Zariadres conquered Acilisene and Taron. The conquered peoples of the territories likewise also spoke Armenian, however imperial Aramaic (with a largely strong amalgamation of Persian words) was still the language of the government and the court, a practice derived from the Achaemenid Empire. According to the 5th-century CE Armenian historian Movses Khorenatsi, Artaxias ordered the delimitation of villages and farmland, which has been confirmed by archaeological sites in Armenia. Artaxias used many epithets, one of them being the unidentified Persian word of ʾxšhsrt.
Artaxias founded the city of Artaxata (Middle Persian: Artaxšas-šāt, "joy of arta") on the left side of the Araxes river, which would serve as the capital and seat of the Armenian monarchy until the 2nd-century CE. It is unlikely that the former Carthaginian commander Hannibal took refuge at the Armenian court and played a role in the establishment of the city. In 165/4 BC, Artaxias suffered a defeat to the forces of the Seleucid king Antiochus IV Epiphanes (r. 175 – 164 BC), who had him captured. Nevertheless, in 161/0 BC, Artaxias managed to help the satrap of Media, Timarchus, who rebelled against Seleucid rule. Artaxias died in 160 BC, and was succeeded by his son Artavasdes I.
Dissimilar to their predecessors, the Orontids, the majority of the Artaxiad rulers minted coins. The reverse of the early Artaxiad coin typically shows an eagle standing on a mountain-top, which is presumably Mount Ararat. The eagle, which also appears on the Artaxiad crown, is possibly a portrayal of the Kayanian xᵛarənah ("glory") of Zoroastrianism.