On 22 June 1941, Nazi Germany invaded the Soviet Union.
Estonia issued Soviet stamps with the overprint "Eesti post", but these were only issued in very small numbers and withdrawn soon after issue.
The first issue for the whole of Estonia were three stamps which came on sale 7th August 1941, with both the Estonian and German spelling of Estonia and emblems on the design.
An issue for Pernau came on sale in August 41, but was soon withdrawn. A second version (overprint different) was put on sale in September, but had no postal value, being solely for stamp collectors.
An interesting set was put on sale in September 41, showing views of Estonia, issued to raise funds for Estonia´s rebuilding programme, they remained valid until March 1942 and could be mixed with the German "OSTLAND" issue.