The Pallava dynasty was a South Indian dynasty that existed from 275 CE to 897 CE, ruling a portion of what is today southern India. They gained prominence after the eclipse of the Satavahana dynasty IOTL, whom the Pallavas served as feudatories. They became a major power during the reign of Mahendravarman I (571–630 CE) and Narasimhavarman I (630–668 CE), and dominated the Telugu and northern parts of the Tamil region for about 600 years until the end of the 9th century. Throughout their reign they were in constant conflict with both Chalukyas of Badami in the north and the Tamil kingdoms of Chola and Pandyas in the south, and were finally defeated by the Chola kings in the 9th century CE.
Pallavas are most noted for their patronage of architecture, the finest example being the Shore Temple, a UNESCO World Heritage Site in Mahabalipuram. The Pallavas, who left behind magnificent sculptures and temples, established the foundations of medieval South Indian architecture. The founders of Salakanagara and Tarumanagara, the first Javanese kingdoms, were an Indian trader and the prince of one of the Pallavas' vassals; and the Pallavas were the first to dominate maritime trade across the region of South-East Asia, developing the Pallava script which was exported eastwards around the 6th century CE and led to the genesis of almost all Southeast Asian writing systems.
These include Grantha, Javanese, Burmese, Thai, Sinhalese, Kawi, Baybayin, Mon, Khmer, Tai Tham, Lao, and the New Tai Lue alphabets, all of which are either direct or indirect derivations from the Kadamba-Pallava alphabet. So then, how much more large and powerful could a Pallava Empire have been in an ATL in which they chose to adopt a more colonial Imperial approach?