The Sanctuary of Artemis Orthia was built near the banks of the Evrotas River, near the ancient town of Limnon. It was one of the most significant sanctuaries of the Spartan cult and was associated with the education of young Spartans.
Early on, the deity worshipped was referred to as Orthias who was considered the goddess of salvation and fertility, as well as the protector of vegetation. Later on, the cult was linked to that of Artemis and the temple became a center of religious education for young people. During the Imperial Period, it served as the site of bloody spectacles performed in accordance to the customs of the time.
The temple was excavated by the British Archaeological School of Athens (1906-1910). We can now distinguish three sections: (1) a great Roman structure (during the Imperial Period, the shrine of Orthias had taken the form of a circular amphitheatre where the temple held the position of the stage), (2) the remains of an altar in the center of the site and (3) a section of the temple to the west. The temple was built with rough stones in the 6th century BC.
The presence of the impressive amphitheatre indicates that people gathered there to observe rituals performed in honour of Artemis Orthia.
From the numerous inscriptions found at the temple, it seems that the goddess was associated with the education of Spartan children under the age of 13.
Below this temple, a smaller, older temple has been discovered which probably dates back to the 9th century BC.
https://www.exploresparta.gr/tourism/en/the-sanctuary-of-artemis-orthia/