There are four vedas namely Rigveda, Samaveda, Yajurveda and Atharva veda.
Rig Veda is divided into ten chapters (mandalas) and has 10552 richas (also called shlokas or mantras) which were revealed by parmeshwar to 414 risies including 31 lady risikas. A group of richas devoted to one deity (devata) is called Sukta. There are 1028 Suktas in Rigveda. Internal sequencing of mandalas on a time scale has not yet been universally agreed upon
Samaveda has 1875 richas out of which 1800 richas are found in Rigveda. Some experts put the number of samaveda richas borrowed from Rigveda at 1783. Two samaveda richas (1832 and 1833) can be located in Yajurveda, Samaveda richa 588 occurs at AV (6.33.1). While borrowing about 106 richas underwent some changes to give musical tone.
Yajurveda has 40 Adhyayas (Chapter) and 1975 richas. The 40th Adhyaya of Yajurveda is also called Eshavaspyopanishad. Richas of Yajurveda are more in the nature of prose devoted to performing yagyas. 794 Rig Veda richas appear in Yajurveda.
Atharva Veda is divided into twenty Kands (Chapters) and has 5977 richas (Whitney & Joshi) out of which 1200 richas are from Rig Veda.
In addition to spirituality and worships Vedas do preach bravery, war making art and valour (purusharth). These encourage achieving objectives with dedication and purusharth.
Though Rig veda richas appear in Samaveda, yajurveda and Atharva Veda but it does not mean that other three Vedas were revealed or composed after Rigveda as there are specific mention of yajurveda, Sama veda and Atharva veda in the Rig veda itself such as in RV (10.90.9) RV (1.7.1) etc.
The river Sarswati has been described as a mighty flowing river in Rigveda (2.41.16) which dried up during 2600 BC to 1900 BC so Rigveda should be older than 2000 BC (Before Christ).