The historian Ismar Elbogen in his "Century of Jewish Life", which he wrote before he passed away in 1943 and was published posthumously, places the beginning of the war on Tisha B'Av of 1914.
But I think that Jewish people thought of the war as having begun on Tisha B'Av even from the start of the war itself. We can see this from their memoirs. Let me cite ...
The Rama rules in OC 558 that the prohibitions on wine and meat remain in force for only the night of 11 Av. The Mishna Berura (sk 4) notes that this is meant to be specific, and the other prohibitions do not apply immediately following the fast.
The Tosefta (Taanit 2:12) cited in part in the Bavli (Pesachim 54b) says that pregnant and nursing women must fast on Tisha Bav (in contrast to other minor fast days). No distinction is made for a postponed fast. Such a ruling is uniformly accepted and documented in all the classical codes, including the Mishneh Torah (Taaniyot 5:10) and the Shulchan Arukh (...
Several events are listed in chapter 13 of Megilat Ta'anit:
The Jews in the wilderness were decreed to die in the wilderness and not enter Israel.
The First Temple was destroyed.
The Second Temple was destroyed.
The city of Beitar was conquered.
The City was razed.
בתשעה באב נגזר על אבותינו שלא יכנסו לארץ וחרב הבית בראשונה ובשניה
נלכדה ביתר ונחרשה העיר
Regarding washing on Yom Kippur, the Tur (OH 613) writes:
ביה"כ...ואם היו ידיו מלוכלכות בטיט וצואה מותר לרוחצן שלא אסרו אלא רחיצה של תענוג ...וכן בכל היום אחר שעשה צרכיו וקנח או הטיל מים ושפשף בידיו וכתב גאון מי שהוא איסטניס וצריך לקנח פניו במים ואין דעתו מיושבת עליו כל היום עד שיקנח יכול לקנח בי"ה וכ"כ רי"ץ גיאת אם יש ליכלוך על פניו או על גבי עיניו יכול ...
Here are additional events to the ones already noted in other answers
Expulsion from England (1290): The Jews of England were expelled by King Edward I (chabad.org)
French expulsion (1306): The Jews were expelled from France (from here)
Spanish Expulsion (1492): The Jews of Spain were expelled by King Ferdinand and Queen Isabella on the 9th of Av of 1492, ...
Rav Shumel Kamentzky, cited in sefer Kovetz Halachos pg 231, writes that a nursing woman or someone riding a bus may sit, because it is a necessary thing and not done out of enjoyment.
Sitting on the toilet is a need and not meant for enjoyment and should be the same.
Tanna v'sheeyer - Anything fitting the mood of the day is acceptable (at least without iyun [in-depth analysis]; see also sources cited by @WFB in comments below which are lenient even with regard to iyun). It would be impossible to have a comprehensive list since Torah SheBaal Peh (the oral Torah) is constantly expanding. (My assumption is that these ...
Whether or not tashmish and other private acts of mourning remain forbidden on Shabbat Tisha b'Av is a difference of opinion between the Mechaber and the Rama in Shulchan Aruch OC 554:19 with the Mechaber permitting and the Rama forbidding. Some Achronim debate whether Ashkenazim can rely on the Mechaber in certain pressing circumstances so please CYLOR for ...
There are a variety of things that people do on Tisha B'Av. Many people spend most of the morning reading and discussing the Kinnos. It is also permitted and widespread to learn certain bits of Torah that are relevant to Tisha B'Av. These include Eicha, Iyov, the story of the destruction of the Temple which is related in Gittin 56b-58a and Sanhedrin 104, the ...
The only difference mentioned in Rishonim that I'm aware of regards a circumcision on Sunday 10 Av. The Shulchan Arukh (OC 559:9) rules like the Mordechai that the members of a circumcision (father/self, Mohel, Sandek) can break their fast in the afternoon after Mincha. Most Rishonim though don't mention this and indeed many communities do not practice it (...
This year the ninth day of the month of Av fell on Shabbat. Since fasting on Shabbat is forbidden, the holiday of Tisha b'av (which literally translates as "the Ninth of Av", hence the confusion) was pushed back to the following day, and is observed on the Tenth of Av on the calendar, as required by the relevant halacha.
This excerpt from Halachipedia ...
Havdalah is said Sunday night after the fast, omitting the blessings on spices and the flame (the latter of which is said on its own next to a flame on Saturday night). (Shulchan Aruch OC 556)
Attah Chonantanu is said as usual Saturday night and Shmoneh Esrei is still not repeated if forgotten (OC 294:3)
from my shul newsletter
No havdala on cup, no besamim.
At 9:02pm or after, say "Baruch Hamavdil Ben Kodesh L'chol"
(not with brocha). Remove shoes. (We say brocha of "Borei
Meorei Haish" in shul.)
Sunday night; Havdala on cup. No candle or besamim. For
Havdala, one may use grape juice or wine.
One may dry his hands on a towel and then use the damp towel to clean
his eyes and face, as the towel isn’t wet enough to impart enough
water to wet something else (tofach al menat le-hatpiach) (Shulchan
Arukh 554:11). (If one must actually clean one’s eyes in the morning,
it is permitted to do so normally, as it is no different than ...
Today's HalachaText said that clothing should be worn for at least 30 minutes. I asked them for a source and they said this number came from Rav Elyashiv Ztl.
שוב מצאתי I was looking for something else in Rabbi Simcha Bunim Cohen's Laws of the Three Weeks, and found that he quotes Rav YS Elyashiv there as saying a half an hour (page 85); in a footnote he ...
It's brought down in some Sichos from the Lubavitcher Rebbe that there's a question: How can Hashem destroy the Beis Hamikdosh? There is halochos against destroying even a Shul.
The answer is that it was destroyed in order to build a nicer and better one. So the destruction -tisha b'av- is connected with the rebuilding -moshiach-.
This is a matter of dispute between the Rishonim.
The Rambam in his commentary to the Mishna (Rosh Hashana 1, 3) wrote that the people observed the fast of Tisha b'Av even during the period of the second temple. http://www.hebrewbooks.org/pdfpager.aspx?req=37942&st=&pgnum=202
However Rabbi Shimon ben Tzemach Duran (Shut Tashbetz 2, 271) wrote that ...
Two thousand years beforehand, they may not have said this text.
Rambam's text, for example, does not have it, nor do Seder Rav Amram Gaon (ed. Harpenes: Seder Tisha B'av), or Seder Rav Sa'adya Gaon, which just has השוממה.
Nevertheless, it is present in the Siddur of R. Eleazar Rokeah (ch. 123 p. 637). His Siddur makes clear that the references to being ...
Heinrich Himmler received the formal command from the Nazi Party to initiate the Final Solution, an order which resulted in millions of Jewish deaths. This happened on Tisha B'Av in 5701, which corresponds to August 2, 1941 on the Gregorian calendar. (Source)
We did it in my shul for practical reasons. When you read the megilla out loud, it makes you thirsty. Nobody wants to get really thirsty at the beginning of a 25 hour fast, so you split up the reading so that one person does not have to do the whole thing.
See Taz Siman 524 sk 1(1) (I will not say exactly the same thing but reading the Taz I think an answer to the question). He describes a situation in which the pupils don't have pleasure with the study but the teacher has, and prohibit because the pleasure of the teacher. the teacher is adult and the pupils are children, the teacher is accustomed with the ...
Yalkut Yosef Ta'anit 554.52 brings down a very relevant qualification for learning even those subjects that are allowed to be learned on 9-Av. "Although it is permissible to read all the above (the permitted subject for torah study 554.51,) this is only to read them in a superficial manner. It is forbidden to delve into these subjects and study them ...
The Mishna Berurah in siman 559 writes:
ועיין באחרונים דמותר להניח תחתיו שק או כר קטן. וגם יוכל לישב על ספסל נמוך למי שקשה לו לישב על הארץ:
One may place a bag or a small pillow underneath themselves. Also if one finds it hard to sit on the floor, one may use a low chair.
This is basically the ruling presented in the Pri Migadim who found a middle ...
1 - The Or Sameach תענית ה/ו writes that according to the Avodraham that fasting on Shabbos is only forbidden mi'd'oraisa if it's for the full 24 hours, there is an answer to your question, about the difference between Tisha b'av and other fasts.
All fast days are not pushed off from the Torah, only Tisha'h b'Av which is a 24 hour fast is pushed off min ...
The Three Weeks by Rabbi Cohen pg 145-146
"One should try not to divert one's mind from mourning on Tishah B'Av. Therefore it is proper to refrain from all pleasurable activities, such as taking a stroll, reading the newspaper, listening to the radio, playing games."
The Rama (OC 553:2) writes that one should not לטייל = "take pleasure strolls" even on Erev Tisha b"Av that falls on Shabbat; how much more so must one avoid extraneous activity on Tisha b'Av itself!
The Biur Halacha there quoting the Ma'amar Mordechai drives this point home:
ואי לאו דמיסתפינא מחברייא הו"א דאפילו ביום ט"ב עצמו היה ...
Rabbi Yonosan Eibseshitz address this question in Yaaros Dvash (Chelek 2 Drush 4). As far as I can understand, the simple explanation why a mistaken sanctification by Beis Din was not binding in this case is because (as the Gemora in Rosh Hashana 20a explains) this is not applicable in a case of "מיחזי כשיקרא"; if it appears incorrect to the masses ...