External invasions had a significant impact on the art and culture of India in the post-Mauryan period. The most notable invasions were those of the Greeks, Scythians, Kushans, and Huns. These invasions introduced new artistic styles, techniques, and motifs, which greatly influenced Indian art and culture.

Influence on Art:

• Hellenistic Influence: The Greeks brought with them the Hellenistic style of art, which blended Greek and Indian elements. This style is evident in the Gandhara school of art, which flourished in the northwest region of India, and is characterized by realistic depictions of Buddha and other deities.

• Central Asian Influence: The Scythians and Kushans introduced central Asian motifs, such as the use of animal figures and intricate geometric patterns. This style is evident in the Mathura school of art, which flourished in central India.

• Islamic Influence: The Islamic invasions of the 12th century introduced new architectural styles, such as the use of domes and arches. This style is evident in the Indo-Islamic architecture of the Mughal era.

Influence on Culture:

• Religion: The invasions led to the spread of new religions, such as Buddhism and Islam, which greatly influenced Indian culture.

• Language: The invasions also led to the introduction of new languages, such as Greek and Persian, which had a lasting impact on Indian literature and language.

• Trade: The invasions led to increased trade and cultural exchange between India and other regions, which helped to spread Indian culture and ideas.

In conclusion, external invasions had a profound impact on the art and culture of India in the post-Mauryan period. These invasions introduced new artistic styles, techniques, and motifs, and also led to the spread of new religions, languages, and ideas. As a result, Indian art and culture became more diverse and cosmopolitan, reflecting the country's rich history of cultural exchange and interaction.