Srimad Bhagavatam Canto 10, Chapter 72, Text 14

SB 10.72.14

te vijitya nrpan vira
 ajahrur digbhya ojasa
ajata-satrave bhuri
 dravinam nrpa yaksyate
After defeating many kings with their prowess, these heroic brothers brought back abundant wealth for Yudhisthira Maharaja, who was intent on performing the sacrifice, O King.
Srila Prabhupada writes: “It may be noted that by dispatching his younger brothers to conquer in different directions, King Yudhisthira did not actually intend that they declare war with the kings. Actually, the brothers started for different directions to inform the respective kings about King Yudhisthira’s intention to perform the Rajasuya sacrifice. The kings were thus informed that they were required to pay taxes for the execution of the sacrifice. This payment of taxes to Emperor Yudhisthira meant that the king accepted subjugation before him. In case of a king’s refusal to act accordingly, there was certainly a fight. Thus by their influence and strength, the brothers conquered all the kings in different directions, and they were able to bring in sufficient taxes and presentations. These were brought before King Yudhisthira by his brothers.”
Srimad Bhagavatam Canto 10, Chapter 72, Text 13
Srimad Bhagavatam Canto 10, Chapter 72, Text 15