Kautilya's Arthashastra 2.21.2

2.21.2

śulkādāyinaś catvāraḥ pañca vā sārthopayātān vaṇijo likheyuḥ - ke kutastyāḥ kiyatpaṇyāḥ kva cābhijñānaṃ mudrā vā kṛtā iti //

THE Superintendent of Tolls shall erect near the large gate of the city both the toll-house and its flag facing either the north or the south. When merchants with their merchandise arrive at the toll-gate, four or five collectors shall take down who the merchants are, whence they come, what amount of merchandise they have brought and where for the first time the sealmark (abhijnánamudrá) has been made (on the merchandise).