Did the rules of Manusmṛti apply to Svāyambhuva Manu, Śatarūpā and their immediate descendants?

Question

Traditional Hindus believe that Svāyambhuva Manu (or the current Manu) being the first of mankind laid down the rules for humanity in his Manusmṛti. But did these rules apply to Manu himself and to his immediate progeny?

E.g., Manu 3.5 discourages sapiṇḍa marriages:

She who is not a "sapiṇḍa" of one's mother, not of the same "Gotra" as his Father, and who is not born of (unlawful) intercourse—has been recommended for marriage.—(3.5)

Commenting on Manu 3.11, Medhātithi says sapiṇḍa and sagotra marriages are null and void even if they are performed with due marriage rites:

In the whole of this section on Marriage, wherever the prohibition is not based upon grounds that are not perceptible—e.g., ‘one should marry a maiden who is not his father’s sapiṇḍa,’ etc., (when the grounds of interdiction are trascendental, not perceptible, as in the case of the prohibition of marriage with a diseased girl, etc.),—if the prohibition is disobeyed, the ‘marriage’ itself remains unaccomplished. Hence, if one happens to marry a girl belonging to the same gotra as himself, the marriage, even though performed, would be as good as not performed;

Was this rule followed by Manu and his immediate descendants or was it violated?

Answer 1

As per Vishnu Purana: Part 1: Chapter 15, such rules are not applicable for Manus, Ptajapatis and other sages who were responsible for the creation in the very beginning.

MAITREYA.--Daksha, as I have formerly heard, was born from the right thumb of Brahmá: tell me, great Muni, how he was regenerate as the son of the Prachetasas. Considerable perplexity also arises in my mind, how he, who, as the son of Márishá, was the grandson of Soma, could be also his father-in-law.

PARÁŚARA.--Birth and death are constant in all creatures: Rishis and sages, possessing divine vision, are not perplexed by this. Daksha and the other eminent Munis are present in every age, and in the interval of destruction cease to be 7: of this the wise man entertains no doubt. Amongst them of old there was neither senior nor junior; rigorous penance and acquired power were the sole causes of any difference of degree amongst these more than human beings.

The commentetor further says

116:7 'They are removed', which the commentator explains by 'are absorbed, as if they were fast asleep;' but in every age or Yuga, according to the text--in every Manwantara, according to the comment--the Rishis reappear, the circumstances of their origin only being varied. Daksha therefore, as remarked in the preceding note, is the son of Brahmá in one period, the son of the Prachetasas in another. So Soma, in the Swáyambhuva Manwantara, was born as the son of Atri; in the Chákshusha, he was produced by churning the ocean. The words of our text occur in the Hari Vanśa, with an unimportant variation: 'Birth and obstruction are constant in all beings, but Rishis and those men who are wise are not perplexed by this;' that is, not, as rendered above, by the alternation of life and death; but, according to the commentator on the Hari Vanśa, by a very different matter, the prohibition of unlawful marriages. Utpatti, 'birth of progeny,' is the result of their will; Nirodha, 'obstruction,' is the law prohibiting the intermarriage of persons connected by the offering of the funeral cake; to which Rishis and sages are not subject, either from their matrimonial unions being merely platonic, or from the bad example set by Brahmá, who, according to the Vedas, approached his own daughter; we have already had occasion to advert to (p. 51. n. 5). The explanation of the text, however, given by the commentator appears forced, and less natural than the interpretation preferred above.

Answer 2

No. The Manusmṛti is not meant for our time, nor theirs.

I alluded to it not being our time before, however, I didn't say when it is meant to be for, because it never came up.

First of all, it can't be our time because:

सरस्वतीदृशद्वत्योर्देवनद्योर्यदन्तरम् । तं देवनिर्मितं देशं ब्रह्मावर्तं प्रचक्षते ॥ १७ ॥

sarasvatīdṛśadvatyordevanadyoryadantaram | taṃ devanirmitaṃ deśaṃ brahmāvartaṃ pracakṣate || 17 ||

The region lying between the divine rivers Sarasvati and Dṛṣasvatī which has >been created by the gods,—they call ‘Brahmāvarta’—(17)

Thus, the Sarasvatī river is clearly flowing and is used as a location marker

There are other hints like:

विद्या शिल्पं भृतिः सेवा गोरक्ष्यं विपणिः कृषिः । धृतिर्भैक्षं कुसीदं च दश जीवनहेतवः ॥ ११६ ॥

vidyā śilpaṃ bhṛtiḥ sevā gorakṣyaṃ vipaṇiḥ kṛṣiḥ | dhṛtirbhaikṣaṃ kusīdaṃ ca daśa jīvanahetavaḥ || 116 ||

Learning, handicrafts, working on hire, service, cattle-tending, trade, agriculture, >contentment, begging and money-lending,—these are the ten means of livelihood.—(116)

There are a few hints in the Manusmṛti that food is free in this world (at least enough to live on). Contentment being a method of livelihood is one of the most blatant. (As a side note the literal interpretation of a verse in the same chapter as this implies a Śūdra can become a Brāhmaṇa by serving one, without having to be reborn)

षट् त्रिंशदाब्दिकं चर्यं गुरौ त्रैवेदिकं व्रतम् । तदर्धिकं पादिकं वा ग्रहणान्तिकमेव वा ॥ १ ॥

ṣaṭ triṃśadābdikaṃ caryaṃ gurau traivedikaṃ vratam | tadardhikaṃ pādikaṃ vā grahaṇāntikameva vā || 1 ||

Duties relating to the Three Vedas should be observed under the Preceptor for thirty-six >years, or for half that period, or for a quarter, or precisely till they have been got >up.—(1)

This study period, which can be up to 36 years, is way too long (for one subject) to be practical for our lifespans.

Anyway, the actual timespan the Manusmṛti is given for is actually easily determinable from the fact there are seven Manus and the following verses:

शनकैस्तु क्रियालोपादिमाः क्षत्रियजातयः । वृषलत्वं गता लोके ब्राह्मणादर्शनेन च ॥ ४३ ॥

śanakaistu kriyālopādimāḥ kṣatriyajātayaḥ | vṛṣalatvaṃ gatā loke brāhmaṇādarśanena ca || 43 ||

But by the omission of the sacred rites, and also by their neglect of Brāhmaṇas, the >following Kṣatriya castes have gradually sunk to the position of the low-born.—(43)

पौण्ड्रकाश्चौड्रद्रविडाः काम्बोजा यवनाः शकाः । पारदापह्लवाश्चीनाः किराता दरदाः खशाः ॥ ४४ ॥

pauṇḍrakāścauḍradraviḍāḥ kāmbojā yavanāḥ śakāḥ | pāradāpahlavāścīnāḥ kirātā daradāḥ khaśāḥ || 44 ||

The Puṇḍrakas, the Coḍas, the Draviḍas, the Kāmbojas, the Yavanas, the Śākas, the >Pāradas, the Pahlavas, the Cīnas, the Kirātas, the Daradas and the Khaśas.—(44)

The events above are described in other scriptures and are very close to the modern day. Combining with there being seven Manus implies:

The Manusmṛti applies to a time in the future of this Manvantara we are in

https://www.wisdomlib.org/hinduism/book/manusmriti-with-the-commentary-of-medhatithi/d/doc145593.html

https://www.wisdomlib.org/hinduism/book/manusmriti-with-the-commentary-of-medhatithi/d/doc201858.html

https://www.wisdomlib.org/hinduism/book/manusmriti-with-the-commentary-of-medhatithi/d/doc199771.html

https://www.wisdomlib.org/hinduism/book/manusmriti-with-the-commentary-of-medhatithi/d/doc201774.html