Sage Kashyapa is the Grand Old Sire of Hinduism.
He is one of the Saptha Rishis, Seven Sages of Hinduism
The Rishis determine the Sruthi to be followed.
They change for each Manvantara.
The Rishi are seers who know, and by their knowledge are the makers of shastra and “see” all mantras. The word comes from the root rish Rishati-prapnoti sarvvang mantrang jnanena pashyati sangsaraparangva, etc. The seven great Rishi or saptarshi of the first manvantara are Marichi, Atri, Angiras, Pulaha, Kratu, Pulastya, and Vashishtha. In other manvantara there are other sapta-rshi. In the present manvantara the seven are Kashyapa Atri, Vashishtha, Vishvamitra, Gautama, Jamadagni, Bharadvaja. To the Rishi the Vedas were revealed. Vyasa taught the Rigveda so revealed to Paila, the Yajurveda to Vaishampayana, the Samaveda to Jaimini, Atharvaveda to Samantu, and Itihasa and Purana to Suta. The three chief classes of Rishi are the Brah-marshi, born of the mind of Brahma, theDevarshi of lower rank, and Rajarshi or Kings who became Rishis through their knowledge and austerities, such as Janaka, Ritaparna, etc. Thc Shrutarshi are makers of Shastras, as Sushruta. The Kandarshiare of the Karmakanda, such as Jaimini.
For the present Manvantara,Vaivasvatha Manvatara,Kashyapa is one of the Saptha Rishis.
He s the son-in-law of Daksha Prajapati, the progenitor of Mankind.
Kashyapa is mentioned in all the Hindu Puranas,Sikhism.
He was married to Danu, daughter of Daksha, who was the mother of the Danavas.
On Rishis please read my Post.
The Celts worship Dandu and call themselves as the People/Tribes of Danu.
Please read my post on this.
Kashyapa is mentioned predominantly in the north and northwest of India.
Kashmir, India is named after Kashmir,
Kashmir has a huge lake Satisara.
Sara means lake or a mountain.
I take the view that this refers to Mountain range as Shiva’s wife Sat was born here.
Some legends in Kashmir state that the large lake was called Kasyapa Sira.
Kashyapa Sira came to be known as Kashmir.
Mira in Sanskrit means lake,
Note the word Mariner.
It is from the word Mira, to denote Navigator.
The word Caspian is derived from the name of the Caspi (Persian کاسی), an ancient people that lived to the west of the sea in Transcaucasia. Strabo wrote that “to the country of the Albanians belongs also the territory called Caspiane, which was named after the Caspian tribe(Kaswan, Kashyap Jat clans), as was also the sea; but the tribe has now disappeared”. Moreover, the Caspian Gate, which is the name of a region in Tehran province of Iran, is another possible piece of evidence that they migrated to the south of the sea.
The root of the word Caspian can also be traced to Sanskrit.
In Hinduism, Caspian Sea was called the Kashyapa Sagar.
The Caspian Sea is named after a tribe from the province of Gilan (or Guilan) in Iran. Caspi and Amardi (who lived in the Sepid Rud valley) were the main two tribes during the Achaemenid dynasty era. The Achaemenids ruled around the 5th Century BC.
The sage Kashyap was regarded as the founder of Kashmir. At the time he lived in the area, it is believed that most of the land was submerged under water, and the water body was called Kashyap Sar.
‘According to the Nilmat Purana, the land of Kashmir was occupied by a vast lake called “Satisara”. On the basis of this fact, the word “Kashmir” is derived from Sanskrit “Kashyapa + Mira” which means the sea lake or the mountain of sage Kashyapa. Kashyapa was the originator of Kashmir.'(Yahoo Answers)
Valley of kashmir was occupied by two tribes Pisachas and Nagas.
The Kashmir valley was a vast lake called Satisaras, named after Sati or Parvati the consort of Shiva.
The lake was inhabited by the demon Jalodbhav.
‘Kashmir Region was inhabited by two tribes — the Nagas and thePisachas.
The lake was drained off by leader of the Nagas called Ananta (Anantnag region of Kashmir is named after him) to capture and kill the demon. Ananta later names the valley as Kashapa-mira after his father Kashapa.-Nilamat Purana
Prajapati Kashapa killed Jalodbhava with the help of Brahma, Vishnu and Shiva.
The lake was then drained and comes to be known as Kash-mira after the Rishi Kashayapa’-Rajatharangini by Kalhana.
It may be note that the Iran’s tribes descended from the Hindus and some of them mover to the Caspian .
Hindu Puranas say it was drained.
Maps show it was Drainage Basin.
References and Citation.
Chekc the following Link for the Book by Arthur Avalon on Saptha Rishis and some interesting information on Hinduism