Year 1023 (MXXIII) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar.

Millennium: 2nd millennium
1023 in various calendars
Gregorian calendar1023
Ab urbe condita1776
Armenian calendar472
Assyrian calendar5773
Balinese saka calendar944–945
Bengali calendar430
Berber calendar1973
English Regnal yearN/A
Buddhist calendar1567
Burmese calendar385
Byzantine calendar6531–6532
Chinese calendar壬戌(Water Dog)
3719 or 3659
    — to —
癸亥年 (Water Pig)
3720 or 3660
Coptic calendar739–740
Discordian calendar2189
Ethiopian calendar1015–1016
Hebrew calendar4783–4784
Hindu calendars
 - Vikram Samvat1079–1080
 - Shaka Samvat944–945
 - Kali Yuga4123–4124
Holocene calendar11023
Igbo calendar23–24
Iranian calendar401–402
Islamic calendar413–414
Japanese calendarJian 3
Javanese calendar925–926
Julian calendar1023
Korean calendar3356
Minguo calendar889 before ROC
Nanakshahi calendar−445
Seleucid era1334/1335 AG
Thai solar calendar1565–1566
Tibetan calendar阳水狗年
(male Water-Dog)
1149 or 768 or −4
    — to —
(female Water-Pig)
1150 or 769 or −3
Kou Zhun
Kou Zhun (Pingzhong) (c. 961–1023)


By place



By topic




1020s in England

Events from the 1020s in England.


Al-Kashkari (Arabic: الكسكري‎; born 322 AH/934 CE in Kashkar - died 414 AH/1023 CE in Fushanj) was a hospital physician from Baghdad.In diagnosing mental disorder, al-Kashkari used criteria such the temperament of the patient as indicators to ascertain the nature of the mental disorder: sluggishness and forgetfulness point to a cold temperament, which requires a different treatment from a warm one, which is revealed through insomnia.

Avogadro constant

The Avogadro constant, named after scientist Amedeo Avogadro, is the number of constituent particles, usually molecules, atoms or ions that are contained in the amount of substance given by one mole. It is the proportionality factor that relates the molar mass of a substance to the mass of a sample, is designated with the symbol NA or L, and has the value 6.022140857(74)×1023 mol−1 in the International System of Units (SI).Previous definitions of chemical quantity involved the Avogadro number, a historical term closely related to the Avogadro constant, but defined differently: the Avogadro number was initially defined by Jean Baptiste Perrin as the number of atoms in one gram-molecule of atomic hydrogen, meaning one gram of hydrogen. This number is also known as Loschmidt constant in German literature. The constant was later redefined as the number of atoms in 12 grams of the isotope carbon-12 (12C), and still later generalized to relate amounts of a substance to their molecular weight. For instance, the number of nucleons (protons and neutrons) in one mole of any sample of ordinary matter is, to a first approximation, 6×1023 times its molecular weight. Similarly, 12 grams of 12C, with the mass number 12 (6 protons, 6 neutrons), has a similar number of carbon atoms, 6.022×1023. The Avogadro number is a dimensionless quantity, and has the same numerical value of the Avogadro constant when given in base units. In contrast, the Avogadro constant has the dimension of reciprocal amount of substance. The Avogadro constant can also be expressed as 0.6023... mL⋅mol−1⋅Å−3, which can be used to convert from volume per molecule in cubic ångströms to molar volume in millilitres per mole.

Pending revisions in the base set of SI units necessitated redefinitions of the concepts of chemical quantity. The Avogadro number, and its definition, was deprecated in favor of the Avogadro constant and its definition. Based on measurements made through the middle of 2017 which calculated a value for the Avogadro constant of NA = 6.022140758(62)×1023 mol−1, the redefinition of SI units is planned to take effect on 20 May 2019. The value of the constant will be fixed to exactly 6.02214076×1023 mol−1.

Code page 1023

Code page 1023, also known as CP1023 or E7DEC, is an IBM code page number assigned to the Spanish variant of DEC's National Replacement Character Set (NRCS). The 7-bit character set was introduced for DEC's computer terminal systems, starting with the VT200 series in 1983, but is also used by IBM for their DEC emulation. Similar but not identical to the series of ISO 646 character sets, the character set is a close derivation from ASCII with only eight code points differing.

Double-precision floating-point format

Double-precision floating-point format is a computer number format, usually occupying 64 bits in computer memory; it represents a wide dynamic range of numeric values by using a floating radix point.

Floating point is used to represent fractional values, or when a wider range is needed than is provided by fixed point (of the same bit width), even if at the cost of precision. Double precision may be chosen when the range or precision of single precision would be insufficient.

In the IEEE 754-2008 standard, the 64-bit base-2 format is officially referred to as binary64; it was called double in IEEE 754-1985. IEEE 754 specifies additional floating-point formats, including 32-bit base-2 single precision and, more recently, base-10 representations.

One of the first programming languages to provide single- and double-precision floating-point data types was Fortran. Before the widespread adoption of IEEE 754-1985, the representation and properties of floating-point data types depended on the computer manufacturer and computer model, and upon decisions made by programming-language implementers. E.g., GW-BASIC's double-precision data type was the 64-bit MBF floating-point format.

German submarine U-1023

German submarine U-1023 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine. She was laid down on 20 May 1943 by Blohm & Voss in Hamburg, Germany, and commissioned on 15 June 1944 with Oberleutnant Wolfgang Strenger in command. U-1023 sank one ship and damaged one more for a total of 7,680 GRT. After the war she was sunk in Operation Deadlight.

List of RAL colors

Below is a list of RAL Classic colors from the RAL colour standard. The CIE L*a*b* and RGB Web colors shown are approximate and informative only.

Mole (unit)

The mole is the base unit of amount of substance in the International System of Units (SI). Effective 20 May 2019, the mole is defined as the amount of a chemical substance that contains exactly 6.02214076×1023 (Avogadro constant) constitutive particles, e.g., atoms, molecules, ions or electrons.This definition was adopted in November 2018, revising its old definition based on the number of atoms in 12 grams of carbon-12 (12C) (the isotope of carbon with relative atomic mass 12 Da by definition). The mole is an SI base unit, with the unit symbol mol.

The mole is widely used in chemistry as a convenient way to express amounts of reactants and products of chemical reactions. For example, the chemical equation 2H2 + O2 → 2H2O can be interpreted to mean that 2 mol dihydrogen (H2) and 1 mol dioxygen (O2) react to form 2 mol water (H2O). The mole may also be used to represent the number of atoms, ions, or other entities in a given sample of a substance. The concentration of a solution is commonly expressed by its molarity, defined as the amount of dissolved substance per unit volume of solution, for which the unit typically used is moles per litre (mol/l), commonly abbreviated M.

The term gram-molecule was formerly used for essentially the same concept. The term gram-atom has been used for a related but distinct concept, namely a quantity of a substance that contains an Avogadro's number of atoms, whether isolated or combined in molecules. Thus, for example, 1 mole of MgBr2 is 1 gram-molecule of MgBr2 but 3 gram-atoms of MgBr2.

Mole Day

Mole Day is an unofficial holiday celebrated among chemists, chemistry students and chemistry enthusiasts on October 23, between 6:02 a.m. and 6:02 p.m., making the date 6:02 10/23 in the American style of writing dates. The time and date are derived from Avogadro's number, which is approximately 6.02 × 1023, defining the number of particles (atoms or molecules) in one mole (mol) of substance, one of the seven base SI units.

NGC 1023

NGC 1023 is a barred lenticular galaxy, a member of the NGC 1023 group of galaxies in the Local Supercluster. Distance measurements vary from 9.3 to 19.7 million parsecs (30 to 64 million light-years). The supermassive black hole at the core has a mass of (4.4±0.5)×107 M☉.NGC 1023 is included in Halton Arp's Atlas of Peculiar Galaxies, under the category "Galaxies with Nearby Fragments" under the number 135.

NGC 1058

NGC 1058 is a Seyfert Type 2 galaxy in the NGC 1023 Group, located in the Perseus constellation. It is approximately 27.4 million light years from Earth and has an apparent magnitude of 11.82. It is receding from Earth at 518 kilometers per second (322 mi/s), and at 629 kilometers per second (391 mi/s) relative to the Milky Way.

NGC 891

NGC 891 (also known as Caldwell 23 and Silver Sliver Galaxy) is an edge-on unbarred spiral galaxy about 30 million light-years away in the constellation Andromeda. It was discovered by William Herschel on October 6, 1784. The galaxy is a member of the NGC 1023 group of galaxies in the Local Supercluster. It has an H II nucleus.The object is visible in small to moderate size telescopes as a faint elongated smear of light with a dust lane visible in larger apertures.

In 1999, the Hubble Space Telescope imaged NGC 891 in infrared.

In 2005, due to its attractiveness and scientific interest, NGC 891 was selected to be the first light image of the Large Binocular Telescope.

In 2012, it was again used as a first light image of the Discovery Channel Telescope with the Large Monolithic Imager.Supernova SN 1986J was discovered on August 21, 1986 at apparent magnitude 14.

NGC 925

NGC 925 is a barred spiral galaxy located about 30 million light-years away in the constellation Triangulum. The morphological classification of this galaxy is SB(s)d, indicating that it has a bar structure and loosely wound spiral arms with no ring. The spiral arm to the south is stronger than the northern arm, with the latter appearing flocculent and less coherent. The bar is offset from the center of the galaxy and is the site of star formation all along its length. Both of these morphological traits—a dominant spiral arm and the offset bar—are typically characteristics of a Magellanic spiral galaxy. The galaxy is inclined at an angle of 55° to the line of sight along a position angle of 102°.The galaxy is a member of the NGC 1023 Group, a nearby, gravitationally-bound group of galaxies associated with NGC 1023. However, the nearest member lies at least 650,000 ly (200,000 pc) distant from NGC 925. There is a 10 million solar mass (M☉) cloud of neutral hydrogen attached to NGC 925 by a streamer. It is uncertain whether this is a satellite dwarf galaxy, the remnant of a past tidal interaction, or a cloud of primordial gas.

Tadc mac Briain

Tadc or Tadg mac Briain (died 1023) was the son of Brian Boru and Echrad, daughter of Carlus mac Ailella of Uí Áeda Odba. Tadc had one son, Toirdelbach Ua Briain (Turlough O'Brien), with his wife Mór, daughter of Gilla Brigte Ua Maíl Muaid of Cenél Fiachach.After Brian Boru's death at the battle of Clontarf in 1014, Tadc was a serious contender to the kingship of Munster, rivalling his half brother Donnchad mac Briain. Tadc was assassinated at the instigation of Donnchad in 1023.

Taifa of Seville

The Taifa of Seville (Arabic: طائفة إشبيليّة, Ta'ifat-u Ishbiliyyah) was an Arab kingdom which belonged to the Abbadid family. It originated in 1023 and lasted until 1091, in what is today southern Spain and Portugal.


The tonne ( (listen); non-SI unit, symbol: t), commonly referred to as the metric ton in the United States and Canada, is a non-SI metric unit of mass equal to 1,000 kilograms or one megagram (symbol: Mg). It is equivalent to approximately 2,204.6 pounds, 1.102 short tons (US) or 0.984 long tons (UK). Although not part of the SI, the tonne is accepted for use with SI units and prefixes by the International Committee for Weights and Measures.The tonne is derived from the weight of 1 cubic metre of pure water; 1,000 litres of pure water weighs about one tonne.

United Nations Security Council Resolution 1023

United Nations Security Council resolution 1023, adopted unanimously on 22 November 1995, after recalling all resolutions on the conflicts in the former Yugoslavia, the Council noted the "Basic Agreement on the Region of Eastern Slavonia, Baranja and Western Sirmium" between the Government of Croatia and local Serb representatives.

The Security Council again stressed the need for a negotiated political solution to the conflicts in the former Yugoslavia, including the mutual recognition of states in the territory. It also noted that Eastern Slavonia, Baranja and Western Sirmium (known as Sector East) are integral parts of Croatia. Importance was attached to respect for human rights and fundamental freedoms in those areas.

The "Basic Agreement on the Region of Eastern Slavonia, Baranja and Western Sirmium" agreement signed on 12 November 1995 was welcomed and the request to establish a transitional authority and international force contained in the agreement was recognised. All parties were urged to co-operate with each other and the United Nations Confidence Restoration Operation.

Wulfstan (died 1023)

Wulfstan (sometimes Lupus; died 28 May 1023) was an English Bishop of London, Bishop of Worcester, and Archbishop of York. He should not be confused with Wulfstan I, Archbishop of York, or Wulfstan, Bishop of Worcester. He is thought to have begun his ecclesiastical career as a Benedictine monk. He became the Bishop of London in 996. In 1002 he was elected simultaneously to the diocese of Worcester and the archdiocese of York, holding both in plurality until 1016, when he relinquished Worcester; he remained archbishop of York until his death. It was perhaps while he was at London that he first became well known as a writer of sermons, or homilies, on the topic of Antichrist. In 1014, as archbishop, he wrote his most famous work, a homily which he titled the Sermo Lupi ad Anglos, or the Sermon of the Wolf to the English.

Besides sermons Wulfstan was also instrumental in drafting law codes for both kings Æthelred the Unready and Cnut the Great of England. He is considered one of the two major writers of the late Anglo-Saxon period in England. After his death in 1023, miracles were said to have occurred at his tomb, but attempts to have him declared a saint never bore fruit.

Ælfmær (Bishop of Sherborne)

Ælfmaer was a medieval Bishop of Sherborne.

Ælfmaer was consecrated in 1017. He died in 1023, possibly on 5 April.

Ælfwine of Elmham

Ælfwine was a medieval Bishop of Elmham.

Ælfwine was consecrated before 1019 and died on 12 April between 1023 and 1038.

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