This is my narrative and relevant references from the Books where Tarl's Mother is mentioned.
I make no pronouncements on these matters, but report them as I find them.
Arrive at your own conclusions.
I wish you well,
Very little is known about Tarl's mother, basically just that:
The Priest-King Misk said she died from a "petty" bacillus in Earth's contaminated atmosphere. So it sounds like an airborne disease.
One airborne bacillus is anthrax. (We don't know she died of anthrax. Misk called the disease "petty". But perhaps a Priest-King would consider anthrax petty.)
Tarl's father Matthew was also on Earth during Tarl's first few years but returned to Gor before Tarl's mother died.
Matthew was kept on Gor as a hostage so that Tarl's mother would not speak to Tarl about Gor.
The question has arisen, was Tarl's mother a free companion of Matthew or Matthew's slave?
Reason on what we know, based on these statements by Matthew:
"She, of all of them, I loved most,"Yes, she could have been a free woman and in a free companionship with Matthew.
But for those statements to make any sense, Matthew would have had to have several free companions, certainly more than even just three or four. And then the last statement makes no sense at all.
If Matthew was so interested in being in a free companionship that he found someone new each time the last one ended, it makes no sense that Matthew was not in a free companionship when he first meets Tarl on Gor or when he sees Tarl again at the Sardar Fair or again after Tarl had returned the last egg of the Priest-Kings to the Nest.
Would it not seem reasonable that Matthew would have introduced Tarl to his free companion had he had one?
Now, if you look at those statements and think how they would apply if Tarl's mother was a slave, they make perfect sense.
The only caveat is that Matthew would have freed her before Tarl was born. But since Tarl was also back on Earth at this time, that is certainly reasonable.
You may remark my first name, and I assure you that it gave me quite as much trouble as it might you, particularly during my early school years, when it occasioned almost as many contests of physical skill as my red hair. Let us say simply that it is not a common name, not common on this world of ours. It was given to me by my father, who disappeared when I was quite young. I thought him dead until I received his strange message, more than twenty years after he had vanished. My mother, whom he inquired after, had died when I was about six, somewhere about the time I entered school. Biographical details are tedious, so suffice it to say that I was a bright child, fairly large for my age, and was given a creditable upbringing by an aunt who furnished everything that a child might need, with the possible exception of love.
Even now I can remember the letter to the last word. I think I will carry its simple, abrupt message burned into the cells of my brain until, as it is elsewhere said, I have returned to the Cities of Dust.
Forgive me, but I have little choice in these matters. It has been decided. Do whatever you think is in your own best interest, but the fate is upon you, and you will not escape. I wish health to you and to your mother. Carry on your person the ring of red metal, and bring me, if you would, a handful of our green earth.
Discard this letter. It will be destroyed.
"Your mother?" he asked, his eyes concerned.
"Dead, years ago," I said.
He looked at me. "She, of all of them, I loved most," he said, turning away, crossing the room. He appeared to be affected keenly, shaken. I wanted to cross no sympathy with him, yet I found that I could not help it. I was angry with myself. He had deserted my mother and me, had he not? And what was it now that he felt some regret? And how was it that he had spoken so innocently of "all of them," whoever they might be? I did not want to find out.
Yet, somehow, in spite of these things, I found that I wanted to cross the room, to put my hand on his arm, to touch him. I felt somehow a kinship with him, with this stranger and his sorrow. My eyes were moist. Something stirred in me, obscure, painful memories that had been silent, quiet for many years - the memory of a woman I had barely known, of a gentle face, of arms that had protected a child who had awakened frightened in the night. And I remembered suddenly another face, behind hers.
"Father," I said.
My father regarded me evenly. "She will be the last," he said. "I had no right to let her love me."
I was silent.
He sensed my feeling and spoke brusquely. "Thank you for your gift, Tarl Cabot," he said.
I looked puzzled.
"The handful of earth," he said. "A handful of my native ground."
"You spoke of knowing the Cabots for four hundred years," I said.
"Yes," said Misk, "and your father, who is a brave and noble man, has served us upon occasion, though he dealt only, unknowingly, with Implanted Ones. He first came to Gor more than six hundred years ago."
"Impossible!" I cried.
"Not with the stabilization serums," remarked Misk.
I was shaken by this information. I was sweating. The torch seemed to tremble in my hand.
"I have been working against Sarm and the others for a millennia," said Misk, "and at last - more than three hundred years ago - I managed to obtain the egg from which this male emerged." Misk looked down at the young Priest-King on the stone table. "I then, by means of an Implanted Agent, unconscious of the message being read through him, instructed your father to write the letter which you found in the mountains on your native world."
My head was spinning.
"But I was not even born then!" I exclaimed.
"Your father was instructed to call you Tarl, and lest he might speak to you of the Counter-Earth or attempt to dissuade you from our purpose, he was returned to Gor before you were of an age to understand."
"I thought he deserted my mother," I said.
"She knew," said Misk, "for though she was a woman of Earth she had been to Gor."
"Never did she speak to me of these things," I said.
"Matthew Cabot on Gor," said Misk, "was a hostage for her silence."
"My mother," I said, "died when I was very young."
"Yes," said Misk, "because of a petty bacillus in your contaminated atmosphere, a victim to the inadequacies of your infantile bacteriology."
I was silent. My eyes smarted, I suppose from some heat or fume of the Mul-Torch.
"It was difficult to foresee," said Misk. "I am truly sorry."
"Yes," I said. I shook my head and wiped my eyes. I still held the memory of the lonely, beautiful woman whom I had known so briefly in my childhood, who in those short years had so loved me. Inwardly I cursed the Mul-Torch that had brought tears to the eyes of a Warrior of Ko-ro-ba.
"Why did she not remain on Gor?" I asked.
"It frightened her," said Misk, "and your father asked that she be allowed to return to Earth, for loving her he wished her to be happy and also perhaps he wanted you to know something of his old world."