Get All Activity For A Lead

For any given lead I know I can get it's Activity through the Get Lead Activities endpoint. My problem is I want to get the first ever activity recorded for that lead all the way to the last. Is there a way to do this? If I try I date set way in the past (epoch) I get the following response:

{

  "requestId": "15fe4#153d32d6653",

  "success": true,

  "nextPageToken": "5HGU7ZC75UN24BUTN4FPNOQBN35Z4CKALKKTBL5JNUADVGEJNW3A====",

  "moreResult": true

}

Would I have to go through each pageToken till I get data? Is there a way to get the date of the first activity record for a lead?

Thanks.