Bengali is an Indo-Aryan language that originated in the eastern part of the Indian subcontinent. It is believed to have evolved from Prakrit languages around the 7th century AD. The earliest known Bengali literary works date back to the 10th century AD.
Marathi is also an Indo-Aryan language, but it developed later than Bengali. It is believed to have emerged from a dialect of Maharashtri Prakrit around the 13th century AD. The earliest known Marathi literary works date back to the 13th-14th centuries AD.
Therefore, Bengali is considered to be an older language than Marathi.