The composers of the Rigveda are divided into ten families.  These ten families are identified on the basis of the fact that each family has its own AprI-sUkta.

An AprI-sUkta is a particular type of ritual hymn “consisting of invocations to a series of deified objects, and said to be introductory to the animal sacrifice”.¹

The ten AprI-sUktas, and the ten families of composers to whom they belong, are:

1.   I.13   KaNvas (Kevala-ANgirases)
2.   I.142 ANgirases
3.   I.188 Agastyas
4.   II.3    GRtsamadas (Kevala-BhRgus)
5.   III.4   ViSvAmitras
6.   V.5   Atris
7.   VII.2  VasiSThas
8.   IX.5   KaSyapas
9.   X.70  Bharatas
10. X.110 BhRgus

In addition to hymns and verses composed by members of these ten families, we also have the two following categories of hymns and verses:

11. Those composed jointly by members of different families.

12. Those composed by RSis whose family identity is unknown or unidentifiable.

The family-wise distribution of the hymns in each MaNDala is as follows:

MaNDala I (191 hymns, 2006 verses)

1  KANVAS (27 hymns, 321 verses): 12-23, 36-50
2. ANGIRASES (96 hymns, 1047 verses): 31-35, 51-64, 
    74-98, 100-126, 140-164
3. AGASTYAS (27 hymns, 239 verses): 165-191
5. VISVAMITRAS (18 hymns, 207 verses): 1-11, 24-30
7. VASISTHAS (9 hymns, 91 verses): 65-73
8. KASYAPAS (1 hymn, 1 verse): 99
9. BHARATAS (13 hymns, 100 verses): 127-139

MaNDala II (43 hymns, 429 verses)

4.   GRTSAMADAS (39 hymns, 398 verses): 1-3, 8-43
10. BHRGUS (4 hymns, 31 verses): 4-7

MaNDala III (62 hymns, 617 verses)

5.  VISVAMITRAS (60 hymns, 588 verses): 1-35, 37-61 
11. JOINT (2 hymns, 29 verses): 36, 62
      2.  ANgirases (1 verse): 36.10
      5.  ViSvAmitras (25 verses): 36.1-9, 11; 62.1-15
     11. Joint ViSvAmitras and BhRgus (3 verses): 62.16-18

MaNDala IV (58 hymns, 589 verses)

2. ANGIRASES (58 hymns, 589 verses): 1-58

MaNDala V (87 hymns, 727 verses)

2.   ANGIRASES (3 hymns, 19 verses): 15, 35-36
3.   AGASTYAS (1 hymn, 4 verses): 24
5.   VISVAMITRAS ( 2 hymns, 19 verses): 33-34
6.   ATRIS (79 hymns, 655 verses): 1-14, 16-23, 25-28, 
      30-32, 37-43, 45-87
7.   VASISTHAS (1 hymn, 15 verses): 29
11. JOINT (1 hymn, 15 verses): 44
      6.   Atris (1 verse) 44.13
      8.   KaSyapas (11 verses): 44.1-9, 14-15
      11. Joint Atris and KaSyapas (3 verses): 44.10-12

MaNDala VI (75 hymns, 765 verses)

2. ANGIRASES (75 hymns, 765 verses): 1-75

MaNDala VII (104 hymns, 841 verses)

7. VASISTHAS (102 hymns, 832 verses): 1-100, 103-104
11. JOINT (2 hymns, 9 verses): 101-102
      11. Joint ANgirases and VasiSThas 
            (2 hymns, 9 verses): 101-102

MaNDala VIII (103 hymns, 1716 verses)

1. KANVAS (55 hymns, 933 verses): 1, 3-22, 32-34, 39-41, 
      45, 48-66, 72, 76-78, 81-83, 103
2. ANGIRASES (25 hymns, 460 verses): 23-26, 43-44, 46, 
      68-71, 75, 80, 85-86, 88-90, 92-96, 98-99
3 AGASTYAS (1 hymn, 21 verses): 67
6. ATRIS (7 hymns, 88 verses): 35-38, 73-74, 91
8. KASYAPAS (6 hymns, 74 verses): 27-31, 97
10. BHRGUS (4 hymns, 46 verses): 79, 84, 100-101
11. JOINT (4 hymns, 76 verses): 2, 42, 87, 102
      1. KaNvas (2 verses): 2.41-42
      11. Joint KaNvas and Angirases (40 verses): 2.1-40 
           Joint KaNvas and Atris (1 hymn, 6 verses): 42 
           Joint ANgirases and VasiSThas 
               (1 hymn, 6 verses): 87
           Joint ANgirases and BhRgus 
               (1 hymn, 22 verses): 102

MaNDala IX (114 hymns, 1108 verses)

1.   KANVAS (8 hymns, 50 verses): 2, 41-43, 94-95, 
      104-105
2.   ANGIRASES (30 hymns, 217 verses): 4,27-31, 35-40, 
      44-46, 50-52, 61, 69, 72-74, 80-83, 93, 98, 112
3.   AGASTYAS (2 hymns, 12 verses): 25-26
5.   VISVAMITRAS (5 hymns, 44 verses): 1, 3, 70-71, 84
6.   ATRIS (2 hymns, 16 verses): 32, 68
7.   VASISTHAS (1 hymn, 6 verses): 90
8.   KASYAPAS (36 hymns, 300 verses): 5-24, 53-60, 
      63-64, 91-92, 99-100, 113-114
9.   BHARATAS (2 hymns, 27 verses): 96, 111
10. BHRGUS (14 hymns, 136 verses): 47-49, 62, 65, 
      75-79, 85, 87-89
11. JOINT (6 hymns, 196 verses): 67, 86, 97, 101, 
      107-108
            2.   ANgirases (32 verses): 67.1-3, 7-9; 97.
                        45-48; 107.1, 3; 108.4-13
            4.   GRtsamadas (3 verses): 86.46-48
            5.   ViSvAmitras (8 verses): 67.13-15; 101.
                        13-16; 107.5
            6.   Atris (12 verses): 67.10-12; 86.41-45; 
                        101.1-3; 107.4
            7.   VasiSThas (54 verses): 67. 19-21; 97.1-44; 
                        107.7; 108.1-3, 14-16
            8.   KaSyapas (4 verses): 67.4-6; 107.2
            10. BhRgus (4 verses): 67.16-18; 107.6
            11. Joint ANgirases and VasiSThas 
                        (11 verses): 67.22-32
                        Joint SaptaRSis (19 verses): 107. 8-26
            12. UNKNOWN (8 hymns, 104 verses): 
                        33-34, 66, 102-103, 106, 109-110

MaNDala X (191 hymns, 1754 verses)

1.   KANVAS (1 hymn, 9 verses): 115
2.   ANGIRASES (58 hymns, 485 verses); 11-12, 37, 
      39-44, 47-56, 67-68, 71-72, 75, 79-80, 87-88, 100, 
      105, 111-114, 117-118, 126, 128, 131-132, 134, 
      138, 149, 152, 155-156, 158, 164, 169-170, 
      172-174, 178, 182, 187-188, 191.
3.   AGASTYAS (4 hymns, 40 verses): 57-60
5.   VISVAMITRAS (12 hymns, 91 verses): 89-90, 104, 
      121, 129-130, 160-161, 177, 183-184, 190
6.   ATRIS (8 hymns, 112 verses): 45-46, 61-64, 101, 143
7.   VASISTHAS (26 hymns, 276 verses): 20-29, 38, 65-66, 
      73-74, 83-84, 86, 95, 99, 103, 119, 122, 147, 150, 180
8.   KASYAPAS (3 hymns, 24 verses): 106, 136, 163
9.   BHARATAS (4 hymns, 42 verses): 69-70, 102, 133
10. BHRGUS (24 hymns, 255 verses): 10, 13-19, 77-78, 
      91-93, 97-98, 110, 120, 123, 135, 144, 148, 154, 
      165, 171
11. JOINT (7 hymns, 49 verses): 96, 107, 127, 137, 167, 
      179, 181
            2.  ANgirases (4 verses): 137.1,3; 181. 2-3
            5.  ViSvAmitras (1 verse): 137.5
            6.  Atris (1 verse): 137.4
            7.  VasiSThas (2 verses): 137.7; 181.1
            8.  KaSyapas (1 verse): 137.2
            9.  Bharatas (1 verse): 179.2
            10. BhRgus (1 verse): 137.6
            11. Joint KaNvas and ANgirases 
                  (1 hymn, 8 verses): 127 
                  Joint ANgirases and ViSvAmitras 
                  (1 hymn, 11 verses): 107
                  Joint ANgirases and VasiSThas 
                  (1 hymn, 13 verses): 96
                  Joint ViSvAmitras and BhRgus 
                  (1 hymn, 4 verses): 167
            12.  Unknown (2 verses): 179.1,3
12.  UNKNOWN (44 hymns, 371 verses): 1-9, 30-36, 
      76, 81-82, 85, 94, 108-109, 116, 124-125, 139-142, 
      145-146, 151, 153, 157, 159, 162, 166, 168, 175-176, 
      185-186, 189

Clarifications regarding MaNDala X

MaNDala X is a very late MaNDala, and stands out from the other nine MaNDalas in many respects.  One of these is the general ambiguity in the ascriptions of the hymns to their composers.  In respect of 44 hymns, and 2 other verses, it is virtually impossible even to identify the family of the composer.

In respect of many other hymns and verses, where we have identified the family affiliations of the composers, the following clarifications are in order:

Family 1: KANVAS (1 hymn)

1. Upastuta VArSTihavya (1 hymn): X.115

      a. This RSi practically identifies himself as a KANva 
      in verse 5 of the hymn.

      b. Outside this hymn, three out of four references to 
      Upastuta are by KaNvas (I.36.10, 17; VIII.5.25; 103. 8), 
      and in the fourth reference, Upastuta is named 
      along-with Kali (another KANva RSi, composer 
      of VIII.66).

Family 2: ANGIRASES (19 hymns)

1. Indra VaikuNTha (3 hymns): X.48-50

Saptagu ANgiras, the composer of X.47, is clearly the composer of these three hymns, which constitute a continuation of the theme in hymn 47.  Hymn 47 is addressed to Indra as Indra VaikuNTha, and these three hymns, in the manner of a dialogue-hymn, constitute Indra’s “reply” to Saptagu.

2. AGNEYAS (8 hymns): X.51-53, 79-80, 156, 187-188 
    Agni SaucIka/Sapti VAjambhara: X.51-53, 79,-80 
    Ketu Agneya: X.156
    Vatsa Agneya: X.187
    Syena Agneya: X.188

    a. Agni SaucIka is identifiable with the BharadvAja 
        RSi Agni BArhaspatya (joint composer of VIII. 102).
    b. SUcI is a BharadvAja gotra.
    c. The word VAjambhara is found in only two verses 
        outside this hymn, both by ANgirases: 
        I. 60. 6; IV.1.4.
    d. VAja-m-bhara is clearly an inverted form of 
        Bhara-d-VAja.
    e. The only gotras with Agni are BharadvAja and 
        KaSyapa gotras.

3. SAURYAS (4 hymns): X.37, 158, 170, 181 (joint) 
    AbhitApa Saurya: X.37 
    CakSu Saurya: X.158 
    VibhrAT Saurya: X.170 
    Gharma Saurya:X.181 (joint)
    a. The only gotras with SUrya are BharadvAja 
        and ViSvAmitra gotras.
    b. The only other hymns to SUrya are by g BharadvAja 
        (I.115) and a KaNva (I. 50).
    c. The joint hymn b y Gharma Saurya is with a 
        BharadvAja and a VasiSTha.
    d. A word meaning asura-slayer, asurahan/asuraghna, 
        occuring in X.170. 2, is found elsewhere only in 
        hymns by a BharadvAja (VI. 22. 4) and a VasiSTha 
        (VII.13.1).
   e. The three above hymns by Saurya RSis have 
        repetitions in common only with hymns by 
        ANgirases and by GRtsamada (a descendant 
        of BharadvAja):
                X.37.4: X.127.2 (RAtrI BhdradvAjI)
                JyotiSA bAdhase tamo.
                X.37.10: II.23.15 (GRtsamada Saunahotra)
                DraviNam dhehi citram.
                X.158.5: I.82.3 (Gotama RAhUgaNa)
                SusandRSam tvA vayam.
                X.170.4: VIII.98.3 (NRmedha ANgiras)
                VibhrAjanjyotiSA svaragaccho rocanam divah.

4. AURAVAS (3 hymns): X.11-12, 138
    ANga Aurava: X.138
    HavirdhAna ANgi: X.11-12

The patronymics of these RSis show them to be descendants of Uru ANgiras (joint composer of IX.108).

5. AriStanemi TArkSya (1 hymn): X.178.
    a. The only other hymns to horses are by ANgirases 
        (I.162-163; IV. 38-40) and a VasiSTha (VII. 44).
    b. The word TArkSya, outside this hymn, is found only 
        in one verse by an ANgiras, Gotama RAhUgaNa 
        (1.89.6).
    c. The only hymns which have repetitions in common 
        with X.178 are by VAmadeva Gautama:
                X.178.2: IV.23.10
                   PRthvI bahule gabhIre
                X.178.3: IV.38.10
                   SavasA pañca kRSTIh sUrya iva 
                   jyotiSApastatAna.

Family 5: VISVAMITRAS (9 hymns)

1. PRAJAPATYAS (9 hymns): 90, 107 (joint), 121, 
    129-130, 161, 177, 183-184
    NArAyaNa: X.90
    DakSiNA PrAjApatya: X.107 (joint)
    HiraNyagarbha PrAjApatya: X.121
    PrajApati ParameSThin: X.129
    Yajña PrAjApatya: X.130
    YakSmanASana PrAjApatya: X.161
    PataNga PrAjApatya: X.177
    PrajAvAn PrAjApatya: X.183
    ViSNu PrAjApatya: X.184
a. PrajApati ParameSThin, clearly the patriarch of 
    this group of RSis, is identifiable with PrajApati 
    VaiSvAmitra (composer of III.54-56).
b. The only hymn which has a repetition in common 
    with X.129 (by PrajApati ParameSThin) is III.54 
    (by PrajApati VaiSvAmitra):
        X. 129.6: III.54.5
        Ko addhA veda ka iha pra vocat.
c. All the above hymns deal with the subject of 
    creation.  The only other hymn dealing with this 
    subject is X.190, composed by AghamarSaNa 
    VaiSvAmitra; and the only other verse to which the 
    AnukramaNIs assign the same subject is I.24.1, 
    composed by SunahSepa AjIgarti (VaiSvAmitra).
d. ViSvAmitra is traditionally associated with creation.  
    The epics relate the story of TriSanku, in which 
    ViSvAmitra sets out to teach the Gods a lesson by 
    creating a parallel universe.  He finally desists only 
    when the Gods plead with him and accede to his 
    demand.  But, even today, “duplicate” objects in 
    nature are called ViSvAmitra-sRSTi or ViSvAmitra’s 
    creations.
e. NArAyaNa is a ViSvAmitra gotra; and the hymn by 
    NArAyaNa a, who is not given any patronymic, is 
    placed immediately after a hymn by a ViSvAmitra: 
    Renu VaiSvAmitra (X.89).

Family 7: VASISTHAS (23 hymns)

1. Suvedas SairISI (1 hymn): X. 147
        SairISI is a VasiSTha gotra.

2. Vamra VaikhAnasa (1 hymn): X.99
    a. The word SiSnadeva (X.99.3) is found only once 
        outside this hymn in VII.21.5, composed by 
        VasiSTha MaitrAvaruNI.
        The word SiSnA by itself occurs only thrice in 
        the Rigveda, once in a hymn by a VasiSTha, 
        Vasukra Aindra (X.27.19), and once in a hymn 
        by a VasiSTha associate, Kutsa ANgiras 
        (1.105.8). The third occurence, in X.33.3, is in a 
        hymn by a RSi whose family cannot be identified.
    b. The only hymn which has a repetition in common 
        with this hymn is X.20, composed by a VasiSTha, 
        Vimada Aindra:
                X.99.12: X.20.10
                ISamUrjam sukSitim viSvamAbhAh.

3. Manyu TApasa (2 hymns): X.83-84
    a. Manyu TApasa is identifiable with Manyu 
        VAsiSTha (joint composer of IX.97).
    b. TApasa, an epithet signifying heat or passion, has 
        an added symbolic significance in this case: Tapa 
        is a VasiSTha gotra.
    c. The word Manyu is translated, by Griffith, as a 
        name in only one other hymn, X.73.10, composed 
        by GaurivIti SAktya, a VasiSTha.

4. PurUravas AiLa and UrvaSI (1 hymn): X.95.
    a. Verse 17 of the hymn clearly declares: 
        “I, VasiSTha, call UrvaSI to meet me.” The name 
        VasiSTha is translated by Griffith as “her best love”.
    b. Outside this hymn, the word UrvaSI occurs only 
        twice throughout the Rigveda: once in a hymn 
        by an Atri (V.41.19), where it is an epithet for a 
        deified river; and once in a hymn by a VasiSTha 
        (VII.33.11) where UrvaSI is referred to as the 
        mother of VasiSTha.

5. AINDRAS (18 hymns): X.20-29, 38, 65-66, 86, 96 
        (joint), 103, 119, 180
    Vimada Aindra and VasukRta VAsukra: X.20-26
    Vasukra Aindra: X.27-29
    Indra MuSkavAn: X.38
    VasukarNa VAsukra: X.65-66
    VRSAkapi Aindra: X.86
    Sarvahari Aindra: X.96 (joint)
    Apratiratha Aindra: X.103
    Laba Aindra:X. 119
    Jaya Aindra: X.180
    a. The only hymns, other than X.38, in which Indra 
        is named as composer, are hymns in which the 
        God Indra is depicted as speaking in the first 
        person.  But X.38 does not depict Indra speaking 
        in the first person, and it is clear that Indra here 
        is the name of the composer, who is the patriarch 
        of the Aindra group of RSis in MaNDala X.
    b. Indra is a VasiSTha gotra.
    c. Indra MuSkavAn is identifiable with Indrapramati 
        VAsiSTha (joint composer of IX.97).
    d. The word muSka (X.38.5), which gives the RSi 
        his epithet MuSkavAn, is found only once outside 
        this hymn, in X. 102.4, composed by a Bharata. 
        The Bharatas are very closely associated with the 
        ANgirases and VasiSThas.
    e. X.38.5 refers to the RSi Kutsa.  The Kutsas are 
        very close associates of the VasiSThas: the only 
        reference to Kutsas by non-Kutsas are in hymns 
        by VasiSTha (VII.25.5; X.29.2); the only references 
        to VasiSTha by a non-VasiSTha is in a hymn by 
        a Kutsa (I.112.9); and the only hymn in which a 
        Kutsa figures as a joint composer is IX.97, which 
        is jointly attributed to eleven VasiSTha RSis 
        (including Indrapramati) and a Kutsa.
     f. Vasukra Aindra is identifiable with Vasukri 
        VasiSTha (joint composer of IX.97).
     g. VasukarNa VAsukra calls himself a VasiSTha 
        (in X.65.15), and, in verse 12 of the same hymn, 
        he refers to Vimada (Aindra).
     h. Jaya is a VasiSTha gotra
     i. All the four other hymns (including the joint hymn) 
        have repetitions in common with VasiSThas or 
        their associates:
                X.86.5: VII.104.7 (VasiSTha MaitrAvaruNI)
                X.103.4: VII.32.11 (VasiSTha MaitrAvaruNI)
                X. 119.13: X. 150.1 (MRLIka VAsiSTha): III.9.6.
                         (ViSvAmitra GAthina).
                X.96.13: I.104.9 (Kutsa ANgiras)
                X.96.2: I.9.10 (Madhucchandas VaiSvAmitra):
                X.133.1 (SudAs Paijavana).

Apart from these, the four hymns have only two other repetitions (one of which is in common with a ViSvAmitra).

Family 10: BHRGUS (11 hymns)

1. YAMAYANAS (11 hymns): X.10, 13-19, 135, 144, 154 
    Yama Vaivasvata and YamI VaivasvatI: X.10 
    VivasvAn Aditya: X.13
    Yama Vaivasvata: X.14
    Sankha YAmAyana: X.15
    Damana YAmAyana: X.16
    DevaSravas YAmAyana: X. 17 
    Sankhasuka YAmAyana: X.18 
    Mathita YAmAyana: X.19 
    KumAra YAmAyana: X.135 
    UrdhvakRSana YAmAyana: X.144 
    YamI VaivasvatI: X.154
    a. YAmAyana or YAmyAyaNa is a BhRgu gotra.
    b. Mathita is also a BhRgu gotra.
    c. The alternative names given in the AnukramaNIs 
        for the composer of X.19, Mathita YAmAyana, 
        are BhRgu or Cyavana BhArgava.
    d. Yama is mentioned alongwith ancient, mythical 
        BhRgu RSis, AtharvaNa and USanA KAvya 
        in I.83.5.
    e. Hymn X.14.5 states: “Our fathers are ANgirases, 
        Navagvas, AtharvaNas, BhRgus.” BhRgu hymns 
        in MaNDalas IX and X often identify with both 
        ANgirases and BhRgus (see, for example, 
        IX. 62.9, and the comment on it in Griffith’s 
        footnotes).
    f.  All the above hymns deal with the topics of 
        funerals and death.  Tradition ascribes the 
        initiation of funeral rites and ceremonies to 
        Jamadagni BhArgava.

The family identities of the other composers of MaNDala X are either obvious from their patronymics, or known from the gotra lists, or else unidentifiable.

All this information is summarized in the two following tables:
 

Footnotes: