The Mauryan period (c. 322–185 BCE) marks a significant epoch in the history of Indian art and architecture, characterized by a shift from perishable materials like wood to more durable stone, and a distinct imperial patronage, particularly under Emperor Ashoka. This era witnessed the emergence of monumental art and architecture, laying foundational elements for future Indian artistic traditions.

Key Characteristics and Salient Features:

1. Imperial Patronage and State Art: A defining feature was the extensive patronage by the Mauryan emperors, especially Ashoka, who utilized art and architecture as a means to propagate Buddhism (Dhamma) and assert imperial authority. This led to the creation of grand, state-sponsored projects.

2. Shift to Stone: Unlike earlier periods where wood was the primary building material, the Mauryan era saw a widespread adoption of stone, particularly Chunar sandstone, for monumental structures. This transition allowed for greater durability and grandeur.

3. Mauryan Polish: A distinctive characteristic is the highly polished surface of stone sculptures and pillars, often referred to as 'Mauryan polish' or 'mirror-like polish.' This technique, applied to hard sandstone, gave the objects a lustrous, almost metallic sheen, showcasing advanced craftsmanship.

4. Monolithic Carving: Many Mauryan structures, especially the Ashokan pillars, were carved from a single block of stone (monolithic), demonstrating exceptional engineering and sculptural skills.

5. Symbolism: Mauryan art is rich in symbolism, particularly Buddhist motifs like the wheel (Dharmachakra), lion, bull, elephant, and lotus, which conveyed spiritual and imperial messages.

6. Foreign Influence and Indigenous Elements: While there is evidence of Achaemenid (Persian) influence, particularly in the bell-shaped capitals of pillars and the use of polished stone, Mauryan art also developed unique indigenous styles and motifs, blending external ideas with local traditions.

Major Forms of Mauryan Art and Architecture:

1. Palaces: The Mauryan capital at Pataliputra (modern Patna) housed an impressive wooden palace, described by Megasthenes as rivaling the palaces of Susa and Ecbatana. Though largely perished, its grandeur suggests sophisticated architectural planning and craftsmanship in wood.

2. Ashokan Pillars: These monolithic pillars, inscribed with Ashoka's edicts, are the most iconic examples of Mauryan art. They typically consist of a highly polished shaft, topped by a capital featuring an abacus and animal figures. The most famous is the Sarnath Lion Capital, which originally supported a Dharmachakra and is now India's national emblem. Other notable pillars include those at Lauriya Nandangarh and Rampurva, featuring single animal figures like a bull or lion. These pillars served both as ethical proclamations and symbols of imperial power.

3. Stupas: While stupas existed before the Mauryan period as simple earthen mounds, Ashoka is credited with building numerous stupas to enshrine the relics of the Buddha. The original core of the Great Stupa at Sanchi and the stupa at Bharhut are believed to have Mauryan origins, later enlarged and embellished in subsequent periods. These structures were hemispherical domes, symbolizing the cosmos and housing sacred relics.

4. Rock-cut Caves: The Mauryans pioneered rock-cut architecture in India. Ashoka and his grandson Dasharatha dedicated several rock-cut caves, such as the Barabar Caves (e.g., Lomas Rishi Cave, Sudama Cave) and Nagarjuni Caves, to the Ajivika sect. These caves are characterized by their highly polished interior walls, simple facades, and often barrel-vaulted or circular chambers, demonstrating remarkable precision in carving hard rock.

5. Sculpture: Apart from the pillar capitals, Mauryan sculpture includes large, free-standing figures, often depicting Yakshas (male nature spirits) and Yakshinis (female nature spirits). The Didarganj Yakshini, with its polished surface and sensuous form, is a prime example. Terracotta figures, representing popular art, were also produced, though generally less refined than the court-sponsored stone sculptures.

In conclusion, Mauryan art and architecture represent a pivotal phase in Indian history, marked by a transition to stone, imperial patronage, sophisticated craftsmanship, and a blend of indigenous and foreign influences. Its enduring legacy is evident in the monumental pillars, rock-cut caves, and the foundational elements it provided for the rich artistic traditions that followed.