Tamar is mentioned 7 times in scripture, across 4 books of both testaments. First named in scripture around 1752 BC.
The daughter-in-law of Judah, to whose eldest son, Er, she was married (Gen. 38:6). After her husband’s death, she was married to Onan, his brother (8), and on his death, Judah promised to her that his third son, Shelah, would become her husband. This promise was not fulfilled, and hence Tamar’s revenge and Judah’s great guilt (38:12-30).