Albanian
A single-language branch of Indo-European spoken in the state of Albania and divided there into two main dialects. Attestations do not go back further than the 15th century.

Anatolian
An extinct branch of Indo-European spoken in central Turkey and not discovered until the early 20th century. Its main representative is Hittite the language of the Hittite empire (1700-1200 BC).

Armenian
This is a branch of its own and is not attested until the 9th century in a translation of the bible. It divides into East and West Armenian.

Balto-Slavic
A putative combined branch of Indo-European which early divided into Baltic (Lithuanian [written texts date from the 16th century], Latvian and Old Prussian) and Slavic. The latter subdivides into West Slavic (Polish, Czech, Slovak, Sorbian), East Slavic (Russian, Belorussian, Ukrainian) and Southern Slavic (Slovenian, Croatian, Serbian, Macedonian, Bulgarian). Its oldest form is Old Church Slavonic, attested from the 9th century in the area of present-day Bulgaria.

Celtic
Found in Galatia (Asia Minor) until the 5th century AD. Known from inscriptions in Gaul and Iberia. Later forms are found on the British Isles (P-Celtic in Britain and Q-Celtic in Ireland). Written material goes back to about 600 for Old Irish. Ogam, an early rune-like script for inscriptions, dates back somewhat further.

Germanic
The runic alphabet used for North Germanic dates from the 3rd century. Gothic (East Germanic) is found from the 4th century, chiefly in the translation of the New Testament by Bishop Wulfila. The West Germanic languages are attested from the 6th and 7th centuries (Old English and Old High German respectively).

North: Icelandic, Faroese, Swedish, Norwegian (Bokmål+Nynorsk), Danish
West: English, German (Yiddish), Frisian, Low German, Dutch (Afrikaans), Flemish
East: Gothic

Hellenic
An early attested branch of Indo-European which consists of the various dialects of ancient Greek. Homeric Greek is attested from approx. 800 BC, though the inscriptions on Crete known as Linear B document Mycenaean Greek, a much earlier form which goes back to about the 14th century BC.

Indo-Iranian
A combined branch of Indo-European which consists of Iranian, from which the modern Iranian languages and Kurdish are derived, and Indic. The oldest classical form of the latter is called Sanskrit and goes back to the early second millennium BC and is attested in sacred texts called the Vedas. The many Indo-European languages of present-day India are the modern representatives of this branch.

Italic
A branch of Indo-European which appears on the Italian peninsula. It consists chiefly of Latin and Oscan-Umbrian. The only continuation is Latin which of course later branches into the various Romance languages. The earliest attestations are inscriptions from the 6th century BC.

Tocharian
This is an Indo-European language which used to be spoken in western China and which died out after the first millennium AD. There are two recognisable forms, Tocharian A and Tocharian B. Documents of it from the7th century were discovered at the end of the 19th century by a German expedition.

The West Germanic languages

3rd / 4th century
     Runes (North Germanic)

4th century
     Gothic (East Germanic

7th century
     Old English

8th century
     Old High German; Old Saxon

12th century
     Old Low Franconian

14th century
     Old Frisian