The Western Satraps, or Western Kshatrapas (Brahmi: , Mahakṣatrapa, "Great Satraps") were Indo-Scythian (Saka) rulers of the western and central parts of India (extending from Saurashtra in the south and Malwa in the east, covering modern-day Sindh, Gujarat, Maharashtra, Rajasthan and Madhya Pradesh states), between 35 and 415 CE. The Western Satraps were contemporaneous with the Kushans who ruled the northern part of the Indian subcontinent, and were possibly vassals of the Kushans. They were also contemporaneous with the Satavahana who ruled in Central India. They are called "Western Satraps" in modern historiography in order to differentiate them from the "Northern Satraps", who ruled in Punjab and Mathura until the 2nd century CE.
The power of the Western Satraps started to decline in the 2nd century CE after the Saka rulers were defeated by the Emperor Gautamiputra Satakarni of the Satavahana dynasty. After this, the Saka kingdom revived, but was ultimately defeated by Chandragupta II of the Gupta Empire in the 4th century CE.
Name
They are named Western Satraps in contrast to the "Northern Satraps" who ruled around East Punjab and the area of Mathura, such as Rajuvula, and his successors under the Kushans, the "Great Satrap" Kharapallana and the "Satrap" Vanaspara.

Although they called themselves "Satraps" on their coins, leading to their modern designation of "Western Satraps", Ptolemy in his 2nd century "Geographia" still called them "Indo-Scythians". The word Kṣatrapa has the same origin as the word satrap and are both descended from Median xšaθrapāvan-, which means viceroy or governor of a province, and according to John Marshall, the word kṣatrapa means the viceroy of the "King of kings". The title of the Mahakṣatrapa or the "Great Satrap" was given to the ruling Satrap, and the title of kṣatrapa was given to the heir apparent. The western Kshatrapas were also known as Sakas to Indians.
The Sakas of Western India spoke the Saka language, also known as Khotanese as it is first attested in the Tarim Basin.
History
First expansion: Kshaharata dynasty (1st century CE)
The Western Satraps are thought to have started with the rather short-lived Kshaharata dynasty (also called Chaharada, Khaharata or Khakharata depending on sources). The term Kshaharata is also known from the 6 CE Taxila copper plate inscription, in which it qualifies the Indo-Scythian ruler Liaka Kusulaka. The Nasik inscription of the 19th year of Sri Pulamavi also mentions the Khakharatavasa, or Kshaharata race.

The earliest Kshaharata for whom there is evidence is Abhiraka, whose rare coins are known. He was succeeded by Bhumaka, father of Nahapana, who only used on his coins the title of Satrap, and not that of Raja or Raño (king). Nahapana's rule is variously dated to 24-70 CE, 66-71 CE, or 119–124 CE, according to one of his coins, which bear Buddhist symbols, such as the eight-spoked wheel (dharmachakra), or the lion seated on a capital, a representation of a pillar of Ashoka.
Nahapana succeeded him, and became a very powerful ruler. He occupied portions of the Satavahana Empire in western and central India. Nahapana held sway over Malwa, Southern Gujarat, and Northern Konkan, from Bharuch to Sopara and the Nasik and Poona districts. At that time, the area northwest of the Western Satraps in Baluchistan was ruled by the Paratarajas, an Indo-Parthian polity, while the Kushans were expanding their empire in the North.
His son-in-law, the Saka Ushavadata (married to his daughter Dakshamitra), is known from inscriptions in Nasik and Karle and Junnar (Manmodi Caves, inscription of the year 46) to have been viceroy of Nahapana, ruling over the southern part of his territory.

Nahapana established the silver coinage of the Kshatrapas.
Circa 120 CE, the Western Satraps are known to have allied with the Uttamabhadras in order to repulse an attack by the Malavas, whom they finally crushed. The claim appears in an inscription at the Nashik Caves, made by the Nahapana's viceroy Ushavadata:
...And by order of the lord I went to release the chief of the Uttamabhadras, who had been besieged for the rainy season by the Malayas, and those Malayas fled at the mere roar (of my approaching) as it were, and were all made prisoners of the Uttamabhadra warriors.

Support of Indian religions
An important inscription related to Nahapana in the Great Chaitya at Karla Caves shows his support of Buddhism and Hinduism:
Success!! By Ushabadata, the son of Dinaka and the son-in-law of the king, the Kshaharata, the Kshatrapa Nahapana, who gave three hundred thousand cows, who made gifts of gold and a tirtha on the river Banasa, who gave to the Devas and Brahmanas sixteen villages, who at the pure tirtha Prabhasa gave eight wives to the Brahmanas, and who also fed annually a hundred thousand Brahmanas- there has been given the village of Karajika for the support of the ascetics living in the caves at Valuraka without any distinction of sect or origin, for all who would keep the varsha.
Construction of Buddhist caves
The Western Satraps are known for the construction and dedication of numerous Buddhist caves in Central India, particularly in Maharashtra and Gujarat. It is thought that Nahapana ruled at least 35 years in the region of Karla, Junnar and Nasik, giving him ample time for construction work there.

Numerous inscriptions in the caves are known, which were made by the family of Nahapana: six inscriptions in Nasik Caves, one inscription at Karla Caves, and one by Nahapana's minister in the Manmodi Caves at Junnar. At the same time, "Yavanas", Greeks or Indo-Greeks, also left donative inscriptions at the Nasik Caves, Karla Caves, Lenyadri and Manmodi Caves.
Great Chaitya hall at Karla Caves
In particular, the chaitya cave complex of the Karla Caves, the largest in South Asia, was constructed and dedicated in 120 CE by the Western Satraps ruler Nahapana.
Cave No.10 of Nasik, the 'Nahapana Vihara'
Parts of the Nasik Caves, also called Pandavleni Caves, were also carved during the time of Nahapana.

The inscriptions of cave no.10 in the Nasik Caves near Nasik, reveal that in 105-106 CE, Kshatrapas defeated the Satavahanas after which Kshatrapa Nahapana’s son-in-law and Dinika's son- Ushavadata donated 3000 gold coins for this cave as well as for the food and clothing of the monks. Usabhdatta's wife (Nahapana's daughter), Dakshmitra also donated one cave for the Buddhist monks. Cave 10 - 'Nahapana Vihara' is spacious with 16 rooms.
Two inscriptions in Cave 10 mention the building and the gift of the whole cave to the Samgha by Ushavadata, the Saka son-in-law and viceroy of Nahapana:
Success! Ushavadata, son of Dinika, son-in-law of king Nahapana, the Kshaharata Kshatrapa, (...) inspired by (true) religion, in the Trirasmi hills at Govardhana, has caused this cave to be made and these cisterns.
Success! In the year 42, in the month Vesakha, Ushavadata, son of Dinika, son-in-law of king Nahapana, the Kshaharata Kshatrapa, has bestowed this cave on the Samgha generally....
According to the inscriptions, Ushavadata accomplished various charities and conquests on behalf of his father-in-law. He constructed rest-houses, gardens and tanks at Bharukachchha (Broach), Dashapura (Mandasor in Malwa), Govardhana (near Nasik) and Shorparaga (Sopara in the Thana district).
Junnar dedication
A dedication in the Lenyadri complex of the Junnar caves (inscription No. 26 in Cave VI of the Bhimasankar group of caves), mentions a gift by Nahapana's prime minister Ayama in the "year 46":
The meritorious gift.... of Ayama of the Vachhasagotra, prime minister of the King Mahakshatrapa the lord Nahapana
This inscription, the last one of the reign of Nahapana, suggests that Nahapana may have become an independent ruler since he is described as a King.
International trade: the Periplus of the Erythraean Sea
Nahapana is mentioned in the Periplus of the Erythraean Sea under the name Nambanus, as ruler of the area around Barigaza:
Beyond the gulf of Baraca is that of Barygaza and the coast of the country of Ariaca, which is the beginning of the Kingdom of Nambanus and of all India. That part of it lying inland and adjoining Scythia is called Abiria, but the coast is called Syrastrene. It is a fertile country, yielding wheat and rice and sesame oil and clarified butter, cotton and the Indian cloths made therefrom, of the coarser sorts. Very many cattle are pastured there, and the men are of great stature and black in color. The metropolis of this country is Minnagara, from which much cotton cloth is brought down to Barygaza.
Under the Western Satraps, Barigaza was one of the main centers of Roman trade with India. The Periplus describes the many goods exchanged:
There are imported into this market-town (Barigaza), wine, Italian preferred, also Laodicean and Arabian; copper, tin, and lead; coral and topaz; thin clothing and inferior sorts of all kinds; bright-colored girdles a cubit wide; storax, sweet clover, flint glass, realgar, antimony, gold and silver coin, on which there is a profit when exchanged for the money of the country; and ointment, but not very costly and not much. And for the King there are brought into those places very costly vessels of silver, singing boys, beautiful maidens for the harem, fine wines, thin clothing of the finest weaves, and the choicest ointments. There are exported from these places spikenard, costus, bdellium, ivory, agate and carnelian, lycium, cotton cloth of all kinds, silk cloth, mallow cloth, yarn, long pepper and such other things as are brought here from the various market-towns. Those bound for this market-town from Egypt make the voyage favorably about the month of July, that is Epiphi.
Goods were also brought down in quantity from Ujjain, the capital of the Western Satraps:
Inland from this place and to the east, is the city called Ozene, formerly a royal capital; from this place are brought down all things needed for the welfare of the country about Barygaza, and many things for our trade: agate and carnelian, Indian muslins and mallow cloth, and much ordinary cloth.
Some ships were also fitted out from Barigaza, to export goods westward across the Indian Ocean:
Ships are also customarily fitted out from the places across this sea, from Ariaca and Barygaza, bringing to these far-side market-towns the products of their own places; wheat, rice, clarified butter, sesame oil, cotton cloth (the monache and the sagmatogene), and girdles, and honey from the reed called sacchari. Some make the voyage especially to these market-towns, and others exchange their cargoes while sailing along the coast.
Pompei Lakshmi
An Indian statuette, the Pompeii Lakshmi, was found in the ruins of Pompei and is thought to have been the result of Indo-Roman trade relations in the 1st century CE. There is a possibility that the statuette found its way to the west during the rule of Western Satrap Nahapana in the Bhokardan area, and was shipped to Rome from the port of Barigaza.
Defeat by Gautamiputra Satakarni
Nahapana and Ushavadata were ultimately defeated by the powerful Satavahana king Gautamiputra Satakarni. Gautamiputra drove the Sakas from Malwa and Western Maharashtra, forcing Nahapana west to Gujarat. His victory is known from the fact that Gautamiputra restruck many of Nahapana's coins (such a hoard was found in Jogalthambi, Nashik District),) and that he claimed victory on them in an inscription at Cave No. 3 of the Pandavleni Caves in Nashik:
Gautamiputra Satakarni (…) who crushed down the pride and conceit of the Kshatriyas; who destroyed the Sakas (Western Satraps), Yavanas (Indo-Greeks) and Pahlavas (Indo-Parthians), who rooted out the Khakharata family (the Kshaharata family of Nahapana); who restored the glory of the Satavahana race.
Colonization of Java and Sumatra
It seems that the Indian colonisation of the islands of Java and Sumatra took place during the time of the Western Satraps. People may have fled the sub-continent due to the conflicts there. Some foundation legends of Java describe the leader of the colonists as Aji Saka, a prince from Gujarat, at the beginning of the Shaka era (which is also the Java era).
Kardamaka dynasty, family of Castana (1st–4th century)
A new dynasty, called the Bhadramukhas or Kardamaka dynasty, was established by the "Satrap" Castana. The date of Castana is not certain, but many believe his reign started in the year 78 CE, thus making him the founder of the Saka era. This is consistent with the fact that his descendants (who we know used the Saka era on their coins and inscriptions) would use the date of their founder as their era. Castana was satrap of Ujjain during that period. A statue found in Mathura together with statues of the Kushan king Kanishka and Vima Taktu, and bearing the name "Shastana" is often attributed to Castana himself, and suggests Castana may have been a feudatory of the Kushans. Conversely, the Rabatak inscription also claims Kushan dominion over Western Satrap territory (by mentioning Kushan control over the capital Ujjain) during the reign of Kanishka (c. 127–150 CE).
Territory under Chastana
The territory of the Western Satraps at the time of Chastana is described extensively by the geographer Ptolemy in his "Geographia", where he qualifies them as "Indo-Scythians". He describes this territory as starting from Patalene in the West, to Ujjain in the east ("Ozena-Regia Tiastani", "Ozene/Ujjain, capital of king Chastana"), and beyond Barigaza in the south.
Moreover the region which is next to the western part of India, is called Indoscythia. A part of this region around the (Indus) river mouth is Patalena, above which is Abiria. That which is about the mouth of the Indus and the Canthicolpus bay is called Syrastrena. (...) In the island formed by this river are the cities Pantala, Barbaria. (...) The Larica region of Indoscythia is located eastward from the swamp near the sea, in which on the west of the Namadus river is the interior city of Barygaza emporium. On the east side of the river (...) Ozena-Regia Tiastani (...) Minnagara.
Rudradaman I (130-150 CE)
Victory against the Satavahanas
Around 130 CE, Rudradaman I, grandson of Chastana, took the title "Mahakshatrapa" ("Great Satrap"), and defended his kingdom from the Satavahanas. The conflict between Rudradaman and Satavahanas became so gruelling, that in order to contain the conflict, a matrimonial relationship was concluded by giving Rudradaman's daughter to the Satavahana king Vashishtiputra Satakarni. The inscription relating the marriage between Rudradaman's daughter and Vashishtiputra Satakarni appears in a cave at Kanheri:
Of the queen ... of the illustrious Satakarni Vasishthiputra, descended from the race of Karddamaka kings, (and) daughter of the Mahakshatrapa Ru(dra)....... .........of the confidential minister Sateraka, a water-cistern, the meritorious gift.
The Satavahanas and the Western Satraps remained at war however, and Rudradaman I defeated the Satavahanas twice in these conflicts, only sparing the life of Vashishtiputra Satakarni due to their family alliance: