TLM-P struck up a friendship with the Prussian explorer,Ludwig Leichhardt. Leichhardt, 'a brilliant intellectual and man of science'¹⁾ was six years older than TLM-P, and arrived in Sydney three years after TLM-P, in 1842. In September that year Leichhardt visited Dalwood where TLM-P was working, and in June 1843 the two travelled to Moreton Bay.²⁾

In September 1843, TLM-P wrote to Leichhardt from Limestone Station at Ipswich.³⁾ The legible parts of the letter reveal that the two men were both, as TLM-P wrote, great travellers. TLM-P had been in Sydney the previous week and was now 'on the Logan River' and planning to sell his current property to go into partnership in another property with a friend Aikman. TLM-P referred to travelling with Leichhardt, asking him if he 'would like again to be “Compagnons de voyage”'[travelling companion]. Leichhardt had a divisive personality, with people tending to either warmly admire or, equally warmly, dislike him.⁴⁾ He was firmly allied with the squatters, as they could sponsor him when he explored the country in return for information about desirable country to settle.⁵⁾ TLM-P was typical of the squatter admiration for Leichhardt, calling Leichhardt in his letter his 'chere amie' (dear friend) and sending news of mutual friends, including Anne,'a very nice girl'. Perhaps it helped that TLM-P could converse easily in French, though there is no indication that he knew Leichhardt's mother tongue. In 1846, TLM-P promised £2 towards a public testimonial to 'Dr. Leichhardt and his party', to help finance their latest exploring expedition.⁶⁾
Leichhardt also sheds light on the youthful TLM-P, making his way alone in a strange country, determined to re-establish his family fortune and status. When he was 22 years old, 'exuberant and self-assured', and superintendent of Rocky Creek station, Leichhardt chatted with a man he encountered on the verandah, a former convict named Waterford. When TLM-P arrived, waterford 'rose to shake hands eith him, but Prior rebuffed him so coldly that the man quietly sat down again. Shortly after that happened, the hut-keeper served the midday meal and, Leichhardt recorded, TLM-P took him (Leichhardt) outside and told him that 'Waterford was a convict who seduced a girl, whom a friend expressly placed under his protection.' TLM-P then said to the man that 'Mr Waterford I regret I cannot be more hospitable towards you, but your midday meal is served in the hut'. 'Explain yourself', said Waterford. Prior replied 'I think I am not of equal rank with you'. Waterford said 'thank you', saddled his horse and rode away leaving his meal untouched. The tale spread and bush folk were incensed as that thought the incident had just to do with snobbery. At Mr Dangar's station 100 miles further on, someone said that they would like to bolt the door on Prior and set the dogs on him. Waterford declared he had been insulted 'by this young fob' and swore that he or his son would take revenge on him. leichhardt sympathised but thought TLM-P lacked finesse and judgment especially as the bush assumed the snub was due to his 'atoned life (as a convict) and 'not for his unatoned' seduction of a girl under his protection. Leichhardt wrote that 'common-sense just dictates being careful in this country and not to know the errors and crimes of its inhabitants.'⁷⁾